Scriptures

Tobit 8:7-8 – “And now, O Lord, I am not taking this sister of mine because of lust, but with sincerity. Grant that I may find mercy and may grow old together with her.” And she said with him, “Amen.” Then they both went to sleep for the night.

Genesis 12:13 – “Please say that you are my sister so that it may go well with me because of you, and that I may live on account of you.”

Genesis 20:2 – Abraham said of Sarah his wife, “She is my sister.”

Genesis 26:6-7 – So Isaac lived in Gerar. When the men of the place asked about his wife, he said, “She is my sister,”

1 Corinthians 7:1-7 – It is good for a man not to touch a woman. Nevertheless, because of sexual immorality, let each man have his own wife, and let each woman have her own husband. Let the husband render to his wife the affection due her, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another except with consent for a time, that you may give yourselves to fasting and prayer; and come together again so that Satan does not tempt you because of your lack of self-control. But I say this as a concession, not as a commandment. For I wish that all men were even as I myself. But each one has his own gift from God, one in this manner and another in that.

 

Tradition / Church Fathers

“Moreover, You shall not, he says, eat the hare. Wherefore? You shall not be a corrupter of boys, nor like such. Because the hare multiplies, year by year, the places of its conception; for as many years as it lives so many it has.” [talking about Sodomy] Letter of Barnabas, Chapter 10

“Moreover, he [Moses] has rightly detested the weasel [Lev. 11:29]. For he means, ‘Thou shall not be like to those whom we hear of as committing wickedness with the mouth with the body through uncleanness [orally consummated sex]; nor shall thou be joined to those impure women who commit iniquity with the mouth with the body through uncleanness’” Letter of Barnabas 10:8 (A.D. 74).

“By reason of chastity, I say, of which there are many kinds, but first, that every one be careful that he ‘come not near a menstruous woman;’ for this the law of God regards as detestable. But though the law had given no admonition concerning these things, should we willingly, like beetles, roll ourselves in filth?” – Peter, Recognitions of Clement, Book 6

“This kind of chastity is to be observed: that sexual intercourse must not take place heedlessly and for the sake of mere pleasure, but for the sake of begetting children. And since this observance is found even among some of the lower animals, it would be a shame if it was not observed by men, who are reasonable and worship God…. From all these things, then, the statement that He propounded is proved, that chastity, which is observed to a certain extent even by those who live in error, should be held much more purely and strictly, in all its forms, as we showed above, by us who follow the truth; and the rather because with us eternal rewards are assigned to its observance..” – Peter, Recognitions of Clement, book 6, chapter 12.

“For in the beginning of the world there were none of these evils, but they took their rise from the impiety of men; and thence, with the constant increase of iniquities, the number of evils has also increased. But for this reason divine providence has decreed a judgment with respect to all men, because the present life was not such that every one could be dealt with according to his deservings. Those things, therefore, which were well and orderly appointed from the beginning, when no causes of evil existed, are not to be judged of from the evils which have befallen the world by reason of the sins of men. In short, as an indication of the things which were from the beginning, some nations are found which are strangers to these evils. For the Seres, because they live chastely, are kept free from them all; for with them it is unlawful to come at a woman after she has conceived, or while she is being purified. No one there eats unclean flesh, no one knows anything of sacrifices; all are judges to themselves according to justice. For this reason they are not chastened with those plagues which we have spoken of; they live to extreme old age, and die without sickness. But we, miserable as we are, dwelling as it were with deadly serpents Ezekiel 2:6 — I mean with wicked men — necessarily suffer with them the plagues of afflictions in this world, but we cherish hope from the comfort of good things to come.” – Recognitions of Clement ,book 8, chapter 48

“Husbands, love your wives, as fellow-servants of God, as your own body, as the partners of your life, and your co-adjutors in the procreation of children. Virgins, have Christ alone before your eyes, and His Father in your prayers, being enlightened by the Spirit. May I have pleasure in your purity . . . Not, however, that I blame the other saints because they entered into the married state, of which I have just spoken. For I pray that, being found worthy of God, I may be found at their feet in the kingdom, as at the feet of Abraham, and Isaac, and Jacob; as of Joseph, and Isaiah, and the rest of the prophets; as of Peter, and Paul, and the rest of the apostles, that were married men. For they entered into these marriages not for the sake of appetite, but out of regard for the propagation of mankind.” – Ignatius of Antioch, Epistle to the Philadelphians, 4.

But whether we marry, it is only that we may bring up children; or whether we decline marriage, we live continently. – Justin Martyr, First Apology, chapter 29

“And our Lord Jesus Christ was born of a virgin, for no other reason than that He might destroy the begetting by lawless desire, and might show to the ruler that the formation of man was possible to God without human intervention. And when He had been born, and had submitted to the other conditions of the flesh — I mean food, drink, and clothing — this one condition only of discharging the sexual function He did not submit to; for, regarding the desires of the flesh, He accepted some as necessary, while others, which were unnecessary, He did not submit to. For if the flesh were deprived of food, drink, and clothing, it would be destroyed; but being deprived of lawless desire, it suffers no harm. And at the same time He foretold that, in the future world, sexual intercourse should be done away with; as He says, “The children of this world marry, and are given in marriage; but the children of the world to come neither marry nor are given in marriage, but shall be like the angels in heaven.” Let not, then, those that are unbelieving marvel, if in the world to come He do away with those acts of our fleshly members which even in this present life are abolished.” – Justin Martyr, On the Resurrection, chapter 3

“Having the hope of eternal life, we despise the things of this life, even to the pleasures of the soul, each of us reckoning his wife whom he has married according to the laws laid down by us, and only for the purpose of having children. For as the husbandman throwing the seed into the ground awaits the harvest, not sowing more upon it, so to us is the procreation of children.” – Athenagoras of Athens, A Plea for Christians, 33.

“Because of its divine institution for the propagation of man, the seed is not to be vainly ejaculated, nor is it to be damaged, nor is it to be wasted” Clement of Alexandria, The Instructor of Children 2:10:91:2 (A.D. 191).

“To have coitus other than to procreate children is to do injury to nature.” Clement of Alexandria, The Instructor of Children 2:10:95:3 (A.D. 191).

And I agree with Antisthenes when he says, If I could catch Aphrodite, I would shoot her; for she has destroyed many of our beautiful and good women. And he says that Love [Ἐρως] is a vice of nature, and the wretches who fall under its power call the disease a deity. For in these words it is shown that stupid people are overcome from ignorance of pleasure, to which we ought to give no admittance, even though it be called a god, that is, though it be given by God for the necessity of procreation. – Clement of Alexandria, The Stromata, book 2

71. The demonstration of these matters being concluded, let us – now quote all the Scriptures which oppose these heretical sophists, and show the right rule of continence that is preserved on grounds of reason. The man of understanding will find out the particular Scripture which deals with each individual heresy, and at the right time will quote it to refute those who teach doctrines contrary to the commandments. Right from the beginning the law, as we have already said, lays down the command, “Thou shalt not covet thy neighbour’s wife,” long before the Lord’s closely similar utterance in the New Testament, — where the same idea is expressed in his own mouth: “You have heard that the law commanded, Thou shalt not commit adultery. But I say, Thou shalt not lust.”9 That the law intended  husbands to cohabit with their wives with self-control and only for the purpose of begetting children is evident from the prohibition which forbids the unmarried man from having immediate sexual relations with a captive woman. If the man has conceived a desire for her, he is directed to mourn for thirty days while she is to have her hair cut; if after this the desire has not passed off, then they may proceed to beget children, because the appointed period enables the overwhelming impulse to be tested and to become a rational act of will.

72. For this reason you could not point to any place in Scripture where one of the ancients approached a pregnant woman;  later, after the child is born and weaned, you might find that marriage relations of husbands and wives were resumed. You will find that Moses’ father kept this principle in mind. After Aaron’s birth three years passed before Moses was born. Again, the tribe of Levi observed this law of nature given by God, although they were fewer in number than any others which came into the promised land.  For a tribe does not easily grow to great numbers if their men have intercourse only within the legal marriage relationship and then wait until the end not only of pregnancy but also of breast-feeding. – Clement of Alexandria, The Stromata, Book 3, Chapter 11 (A.D. 191).

“Not every soil is suitable for receiving seed, and even if it is, not every soil suits every farmer. Similarly, one must not sow upon rocky ground, nor treat the seed with contempt, for the seed is the leader and principal substance of generation, and it contains within itself the inherent principles of nature. To defile what is according to nature with unnatural actions, by directing it into improper channels, is profoundly impious. – Clement of Alexandria, The Stromata, Book 2, Chapter 10

And not only so, but the Lord also showed that certain precepts were enacted for them by Moses, on account of their hardness [of heart], and because of their unwillingness to be obedient, when, on their saying to Him, “Why then did Moses command to give a writing of divorcement, and to send away a wife?” He said to them, “Because of the hardness of your hearts he permitted these things to you; but from the beginning it was not so;” thus exculpating Moses as a faithful servant, but acknowledging one God, who from the beginning made male and female, and reproving them as hard-hearted and disobedient. And therefore it was that they received from Moses this law of divorcement, adapted to their hard nature. But why say I these things concerning the Old Testament? For in the New also are the apostles found doing this very thing, on the ground which has been mentioned, Paul plainly declaring, “But these things I say, not the Lord.” And again: “But this I speak by permission, not by commandment.” And again: “Now, as concerning virgins, I have no commandment from the Lord; yet I give my judgment, as one that has obtained mercy of the Lord to be faithful.” But further, in another place he says: “That Satan tempt you not for your incontinence.” If, therefore, even in the New Testament, the apostles are found granting certain precepts in consideration of human infirmity, because of the incontinence of some, lest such persons, having grown obdurate, and despairing altogether of their salvation, should become apostates from God — it ought not to be wondered at, if also in the Old Testament the same God permitted similar indulgences for the benefit of His people, drawing them on by means of the ordinances already mentioned, so that they might obtain the gift of salvation through them, while they obeyed the Decalogue, and being restrained by Him, should not revert to idolatry, nor apostatize from God, but learn to love Him with the whole heart. – Irenaeus, Against Heresies, book 4, chapter 15, paragraph 2

Where is the fault of pleasure proven here; where the crime of incest? How will one be given to a vice which is not repeated in deed? I am afraid to say what I feel; I am afraid, I say, lest the incest of these women be purer than the chastity of many women. Let the married women examine themselves and seek if they approach their husbands for this reason alone, that they might receive children, and after conception desist. For those women, who appear to be proven incestuous, when they have attained conception, do not later assent to copulation with a man. But some women, for we do not censure all equally, but there are some who serve passion incessantly, like animals without any distinction, whom I would not even compare to the dumb beasts. For even the beasts themselves know, when they have conceived, not to further grant opportunity to their males. The divine Scripture also censures such when it says: “Do not become like the horse and the mule who have no understanding,” and again, “They have become stallions.” But, 0 people of God, “who love Christ in incorruption,” understand the word of the Apostle in which he says: “Whether you eat or drink or whatever else you do, do all to the glory of God.” For his remark after eating and drinking, “whatever else you do,” has designated with a modest word the immodest affairs of marriage, showing that even these acts themselves are performed to the glory of God if they are attended to with a view to posterity alone. – Origen, Homilies on Genesis, 5.4

But now let us see how also, according to our promise, [true] circumcision of the flesh ought to be received. There is no one who does not know that this member, in which the foreskin is seen to be, serves the natural functions of coitus and procreation. If anyone, therefore, is not troublesome in respect to impulses of this kind, nor exceeds the bounds set by the laws, nor has known a woman other than his lawful wife, and, in the case of her also, makes use of her in the determined and lawful times for the sake of posterity alone, that man is to be said to be circumcised in the foreskin of his flesh. But that man is uncircumcised in the foreskin of his flesh who falls down in all lasciviousness and everywhere loiters for diverse and illicit caresses, and is carried along unchecked in every whirlpool of lust. But the Church of Christ, strengthened by the grace of him who has been crucified for it, abstains not only from illicit and impious beds but also from those allowed and legitimate, and flourishes like the virgin bride of Christ with pure and chaste virgins in whom true circumcision of the foreskin of the flesh has been performed and truly God’s covenant and the eternal covenant is preserved in their flesh. – Origen, Homilies on Genesis, 3.6

“[Christian women with male concubines], on account of their prominent ancestry and great property, the so-called faithful want no children from slaves or lowborn commoners, [so] they use drugs of sterility or bind themselves tightly in order to expel a fetus which has already been engendered.” – Hippolytus, Refutation of All Heresies 9:12 (A.D. 225).

Those who take a downward flight, and fall into pleasures, do not desist from grief and labours until, through their passionate desires, they fulfil the want of their intemperance, and, being degraded and shut out from the sanctuary, they are removed from the scene of truth, and, instead of procreating children with modesty and temperance, they rave in the wild pleasures of unlawful amours. But those who, on light wing, ascend into the supramundane life, and see from afar what other men do not see, the very pastures of immortality, bearing in abundance flowers of inconceivable beauty, are ever turning themselves again to the spectacles there; and, for this reason, those things are thought small which are here considered noble — such as wealth, and glory, and birth, and marriage; and they think no more of those things. But yet if any of them should choose to give up their bodies to wild beasts or to fire, and be punished, they are ready to have no care for pains, for the desire of them or the fear of them; so that they seem, while in the world, not to be in the world, but to have already reached, in thought and in the tendency of their desires, the assembly of those who are in heaven. – Methodius, Banquet of the ten virgins, discourse 8, chapter 2

“[Some] complain of the scantiness of their means, and allege that they have not enough for bringing up more children, as though, in truth, their means were in [their] power . . . or God did not daily make the rich poor and the poor rich. Wherefore, if any one on any account of poverty shall be unable to bring up children, it is better to abstain from relations with his wife.” – Lactantius, Divine Institutes 6:20 (A.D. 307).

“God gave us eyes not to see and desire pleasure, but to see acts to be performed for the needs of life; so too, the genital [’generating’] part of the body, as the name itself teaches, has been received by us for no other purpose than the generation of offspring.” – Lactantius, Divine 6:23:18 (A.D. 307).

“When the natural menstruations appear in the wives, do not let their husbands [have intercourse with] them, out of regard for the children that are to be begotten; for the law has forbidden it, for it says: “You shall not come near your wife when she is in her separation” (Leviticus 18:19). Neither let them [have intercourse with] their wives, when they are pregnant. For they do not do this for the begetting of children, but for the sake of pleasure. Now a lover of God ought not to be a lover of pleasure.” – Apostolic Constitutions, 6:5:28.

“[I]f anyone in sound health has castrated himself, it behooves that such a one, if enrolled among the clergy, should cease [from his ministry], and that from henceforth no such person should be promoted. But, as it is evident that this is said of those who willfully do the thing and presume to castrate themselves, so if any have been made eunuchs by barbarians, or by their masters, and should otherwise be found worthy, such men this canon admits to the clergy.” Council of Nicaea I, Canon 1 (A.D. 325).

“You will find some who are so filled with fear of God, that they are able to rule and moderate their hearts. People such as this, once they have conceived of children, refrain from further intercourse. Is this so surprising in human beings, seeing that even the very animals silently tell us, by their example, that they, once they have conceived of offspring, cease to copulate? Once they feel their wombs grow heavy with the seed that has been implanted in them, they give up physical intercourse. They no longer abandon themselves to passion, but devote themselves to the care of their little ones. But as for humans, they have regard neither for their children, nor for God. The former they defile, and the latter they provoke to anger.” – Ambrose of Milan, Commentary on Luke 1:24-25.

“They [certain Egyptian heretics] exercise genital acts, yet prevent the conceiving of children. Not in order to produce offspring, but to satisfy lust, are they eager for corruption.” Epiphanius of Salamis, Medicine Chest Against Heresies 26:5:2 (A.D. 375).

“This proves that you [Manicheans] approve of having a wife, not for the procreation of children, but for the gratification of passion. In marriage, as the marriage law declares, the man and woman come together for the procreation of children. Therefore, whoever makes the procreation of children a greater sin than copulation, forbids marriage and makes the woman not a wife but a mistress, who for some gifts presented to her is joined to the man to gratify his passion.” Augustine, The Morals of the Manichees 18:65 (A.D. 388).

“Why do you sow where the field is eager to destroy the fruit, where there are medicines of sterility [oral contraceptives], where there is murder before birth? You do not even let a harlot remain only a harlot, but you make her a murderess as well…Indeed, it is something worse than murder, and I do not know what to call it; for she does not kill what is formed but prevents its formation. What then? Do you condemn the gift of God and fight with his [natural] laws?…Yet such turpitude…the matter still seems indifferent to many men—even to many men having wives. In this indifference of the married men there is greater evil filth; for then poisons are prepared, not against the womb of a prostitute, but against your injured wife. Against her are these innumerable tricks.” John Chrysostom, Homilies on Romans 24 (A.D. 391).

“[I]n truth, all men know that they who are under the power of this disease [the sin of covetousness] are wearied even of their father’s old age [wishing him to die so they can inherit]; and that which is sweet, and universally desirable, the having of children, they esteem grievous and unwelcome. Many at least with this view have even paid money to be childless, and have mutilated nature, not only killing the newborn, but even acting to prevent their beginning to live.” John Chrysostom, Homilies on Matthew 28:5 (A.D. 391).

“[T]he man who has mutilated himself, in fact, is subject even to a curse, as Paul says, ‘I would that they who trouble you would cut the whole thing off’ [Gal. 5:12]. And very reasonably, for such a person is venturing on the deeds of murderers, and giving occasion to them that slander God’s creation, and opens the mouths of the Manicheans, and is guilty of the same unlawful acts as they that mutilate themselves among the Greeks. For to cut off our members has been from the beginning a work of demonical agency, and satanic device, that they may bring up a bad report upon the works of God, that they may mar this living creature, that imputing all not to the choice, but to the nature of our members, the more part of them may sin in security as being irresponsible, and doubly harm this living creature, both by mutilating the members and by impeding the forwardness of the free choice in behalf of good deeds.” John Chrysostom, Homilies on Matthew 62:3 (A.D. 391).

“Observe how bitterly he [Paul] speaks against their deceivers…‘I would that they which trouble you would cut the whole thing off’ [Gal. 5:12]…On this account he curses them, and his meaning is as follows: ‘For them I have no concern, “A man that is heretical after the first and second admonition refuse” [Titus 3:10]. If they will, let them not only be circumcised but mutilated.’ Where then are those who dare to mutilate themselves, seeing that they draw down the apostolic curse, and accuse the workmanship of God, and take part with the Manichees?” John Chrysostom, Commentary on Galatians 5:12 (A.D. 395)

Our soul hath by nature the love of life, but it lies with us either to loose the bands of nature, and make this desire weak; or else to tighten them, and make the desire more tyrannous. For as we have the desire of sexual intercourse, but when we practice true wisdom we render the desire weak, so also it falls out in the case of life; and as God hath annexed carnal desire to the generation of children, to maintain a succession among us, without however forbidding us from traveling the higher road of continence; so also He hath implanted in us the love of life, forbidding us from destroying ourselves, but not hindering our despising the present life. – John Chrysostom, Homily 85 on the Gospel of John (John 19:24)

The saints entered the married life not to pursue pleasure but for the sake of children. There is in fact a tradition that says they would go with their wives only when the time was suitable for conception. They would not go with them during the lactation period, when they were nursing their young, or when they were with child, because they regarded neither of these times as suitable for coming together…. When Sarah, therefore, who was wise and holy, had observed for a long time that in spite of coming together with her husband she was not conceiving, she abstained from conjugal relations, and since she knew that it was in the order of things that he should have children, she gave him her slave girl as a concubine. This shows the moderation and the absence of jealousy of Sarah and the passionlessness of Abraham, who chose this solution at his wife’s instigation and not on his own imitative and who yielded to her request only in order to give birth to children. – Didymus the Blind, On Abraham 235

“But I wonder why he [the heretic Jovinianus] set Judah and Tamar before us for an example, unless perchance even harlots give him pleasure; or Onan, who was slain because he grudged his brother seed. Does he imagine that we approve of any sexual intercourse except for the procreation of children?” Jerome, Against Jovinian 1:19 (A.D. 393).

“You may see a number of women who are widows before they are wives. Others, indeed, will drink sterility and murder a man not yet born, [and some commit abortion].” Jerome, Letters 22:13 (A.D. 396).

“You [Manicheans] make your auditors adulterers of their wives when they take care lest the women with whom they copulate conceive. They take wives according to the laws of matrimony by tablets announcing that the marriage is contracted to procreate children; and then, fearing because of your law [against childbearing]…they copulate in a shameful union only to satisfy lust for their wives. They are unwilling to have children, on whose account alone marriages are made. How is it, then, that you are not those prohibiting marriage, as the apostle predicted of you so long ago [1 Tim. 4:1–4], when you try to take from marriage what marriage is? When this is taken away, husbands are shameful lovers, wives are harlots, bridal chambers are brothels, fathers-in-law are pimps.” Augustine, Against Faustus 15:7 (A.D. 400).

“For thus the eternal law, that is, the will of God creator of all creatures, taking counsel for the conservation of natural order, not to serve lust, but to see to the preservation of the race, permits the delight of mortal flesh to be released from the control of reason in copulation only to propagate progeny.” Augustine, Against Faustus 22:30 (A.D. 400).

“For necessary sexual intercourse for begetting [children] is alone worthy of marriage. But that which goes beyond this necessity no longer follows reason but lust. And yet it pertains to the character of marriage…to yield it to the partner lest by fornication the other sin damnably [through adultery]…[T]hey [must] not turn away from them the mercy of God…by changing the natural use into that which is against nature, which is more damnable when it is done in the case of husband or wife. For, whereas that natural use, when it pass beyond the compact of marriage, that is, beyond the necessity of begetting [children], is pardonable in the case of a wife, damnable in the case of a harlot; that which is against nature is execrable when done in the case of a harlot, but more execrable in the case of a wife. Of so great power is the ordinance of the Creator, and the order of creation, that . . . when the man shall wish to use a body part of the wife not allowed for this purpose [orally or anally consummated sex], the wife is more shameful, if she suffer it to take place in her own case, than if in the case of another woman.” Augustine, The Good of Marriage 11–12 (A.D. 401).

“I am supposing, then, although you are not lying [with your wife] for the sake of procreating offspring, you are not for the sake of lust obstructing their procreation by an evil prayer or an evil deed. Those who do this, although they are called husband and wife, are not; nor do they retain any reality of marriage, but with a respectable name cover a shame. Sometimes this lustful cruelty, or cruel lust, comes to this, that they even procure poisons of sterility…Assuredly if both husband and wife are like this, they are not married, and if they were like this from the beginning they come together not joined in matrimony but in seduction. If both are not like this, I dare to say that either the wife is in a fashion the harlot of her husband or he is an adulterer with his own wife.” Augustine, Marriage and Concupiscence 1:15:17 (A.D. 419).

“But let those be of good cheer who, being married, use marriage lawfully; who make a marriage according to God’s ordinance, and not of incontinence for the sake of an unbounded license . . . who have entered upon matrimony for the procreation of children, but not for indulgence.” – Cyril of Jerusalem, Catechetical Lectures, 4:25.

“Marriage is honorable, indeed, if it serves for the procreation of children; and the one who has used it, according to the law, is blameless.” – Cyril of Alexandria, Adoration in Spirit and Truth, 15.

“Of fornication, there are three kinds: (1) that which is accomplished by sexual intercourse; (2) that . . . for which we read that Onan, the son of Judah the patriarch, was smitten by the Lord; and which is termed by Scripture ‘uncleanness’ . . . (3) and that which is conceived of in the heart and mind.” – John Cassian, Conferences, 5:11.

“Who is he who cannot warn that no woman may take a potion so that she is unable to conceive or condemns in herself the nature which God willed to be fecund? As often as she could have conceived or given birth, of that many homicides she will be held guilty, and, unless she undergoes suitable penance, she will be damned by eternal death in hell. If a woman does not wish to have children, let her enter into a religious agreement with her husband; for chastity is the sole sterility of a Christian woman.” – Caesarius of Arles, Sermons 1:12 (A.D. 522).

Although the Apostle has mentioned more serious sins, nevertheless we briefly say what they are, lest we seem to prompt despair. Sacrilege, murder, adultery. false testimony, theft, robbery. pride, envy, avarice, and, if it is continued for a long time, anger, drunkenness if continuous, and slander are included in their number. If anyone knows that some of these sins have dominion over him, unless he does penance in a worthy manner and for a long time, if he enjoys it, and further gives abundant alms and refrains from those same sins, he cannot be purged by that passing fire of which the Apostle spoke. Instead, eternal flames will torture him without any remedy. Although what the slight offenses are is known to all of you, still it is necessary to name at least a few of them, since it would take too long to mention them all. As often as anyone takes more than he needs in food or drink, he knows that this amounts to slight sins. As often as a man speaks more than he should or is silent more than is proper; as often as he provokes a poor man who is begging rudely; as often as he wills to eat when others are fasting, even though he is in bodily health, and rises too late for church because he had surrendered to sleep; as often as he knows his wife without the desire for children; as often as he looks tardily for those who are placed in prison, and even more rarely visits the sick; if he has neglected to recall the discordant to harmony; if he has irritated his neighbor or his wife or his child or a servant more than he should; if he has flattered himself more than is right; if he has willingly flattered a superior either of his own accord or out of necessity; if he has prepared exceedingly luxurious or sumptuous feasts for himself while the poor were hungry; if he has occupied himself, either in church or outside of it, with idle stories for which an account must be rendered on the day of judgment; if when we carelessly take an oath we swear falsely, when we could not have done this because of any necessity, and curse with all facility and temerity, although it is written: ‘Nor the evil-tongued will possess the kingdom of God’;3 when we rashly suspect something which usually is not proven to be as we thought, without any doubt we commit sin. There is no doubt that these actions and similar ones belong to the slight offenses which, as I already said, can scarcely be counted. – Caesarius of Arles, Sermon 179

Lawful commerce, therefore, must be for the sake of children, not of pleasure; and must be to procure offspring, not to satisfy vices. But if any man isled not by the desire of pleasure, but only for the sake of getting children, such a man is certainly to be left to his own judgment, either as to entering the church, or as to receiving the mystery of the body and blood of our Lord, which he, who being placed in the fire cannot burn, is not to be forbidden by us to receive. But when, not the love of getting children, but of pleasure prevails, the pair have cause to lament their deed. For this the holy preaching allows them, and yet fills the mind with dread of the very allowance. For when Paul the Apostle said, “ Let him that cannot contain, have his wife;” he presently took care to subjoin, “ But this I say by way of indulgence, not by way of command.” For that is not granted by way of indulgence which is lawful, because it is just; and, therefore, that which he said he indulged, he showed to be an offence. – Bede, The Complete Works of Venerable Bede, volume 2, page 131 (A.D. 673-735)

 

Martin Luther:

“Onan must have been a malicious and incorrigible scoundrel. This is a most disgraceful sin. It is far more atrocious than incest and adultery. We call it unchastity, yes, a sodomitic sin. For Onan goes in to her; that is, he lies with her and copulates, and when it comes to the point of insemination, spills the semen, lest the woman conceive. Surely at such a time the order of nature established by God in procreation should be followed. Accordingly, it was a most disgraceful crime to produce semen and excite the woman, and to frustrate her at that very moment. He was inflamed with the basest spite and hatred. Therefore he did not allow himself to be compelled to bear that intolerable slavery. Consequently, he deserved to be killed by God. He committed an evil deed. Therefore God punished him.”

John Calvin:

“I will content myself with briefly mentioning this, as far as the sense of shame allows to discuss it. It is a horrible thing to pour out seed besides the intercourse of man and woman. Deliberately avoiding the intercourse, so that the seed drops on the ground, is doubly horrible. For this means that one quenches the hope of his family, and kills the son, which could be expected, before he is born.

The wickedness is now as severely as is possible condemned by the Spirit, through Moses, that Onan, as it were, through a violent and untimely birth, tore away the see of his brother out the womb, and as cruel and shamefully was thrown on the earth. Moreover he thus has, as much as was in his power, tried to destroy a part of the human race. When a woman in some way drives away the seed out the womb, through aids, then this is rightly seen as an unforgivable crime*. Onan was guilty of a similar crime, by defiling the earth was his seed, so that Tamar would not receive a future inheritor.” – (Commentary on Genesis)

John Wesley:

“Onan, though he consented to marry the widow, yet to the great abuse of his own body, of the wife he had married and the memory of his brother that was gone, refused to raise up seed unto the brother. Those sins that dishonour the body are very displeasing to God, and the evidence of vile affections. Observe, the thing which he did displeased the Lord – And it is to be feared, thousands, especially single persons, by this very thing, still displease the Lord, and destroy their own souls.” – (Notes on the First Book of Moses, comment on 38:7)