If you bring your gift to the altar, and there remember that your brother has something against you, leave your gift there before the altar, and go your way. First be reconciled to your brother, and then come and offer your gift. Matt. 5:23.
When he opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God. Rev. 6:9.
Let no man deceive himself. If anyone is not within the altar, he is deprived of the bread of God. Ignatius (c. 105, E), 1.51.
He that is within the altar is pure. However, he that is outside of it is not pure. I mean, he who does anything apart from the bishop, the presbyters, and the deacons, such a man is not pure in his conscience. Ignatius (c. 105, E), 1.69.
Therefore, take heed to have only one Eucharist. For there is one flesh of our Lord Jesus Christ and . . . one altar. Ignatius (c. 105, E), 1.81.
It is, therefore, also His will that we, too, should offer a gift at the altar, frequently and without intermission. The altar, then, is in heaven. For our prayers and oblations are directed towards that place. Irenaeus (c. 180, E/ W), 1.486.
The altar, then, that is with us here, the terrestrial one, is the congregation of those who devote themselves to prayers. They have, as it were, one common voice and one mind. Clement of Alexandria (c. 195, E), 2.531.
Will they not believe us when we say that the righteous soul is the truly sacred altar, and that the incense arising from it is holy prayer? Clement of Alexandria (c. 195, E), 2.531.
Does, then, the Eucharist cancel a service devoted to God—or does it bind it more to God? Will not your station be more solemn if you have stood at God’s altar? Tertullian (c. 198, W), 3.687.
Do you think that we conceal what we worship just because we do not have temples and altars? Mark Minucius Felix (c. 200, W), 4.193.
He relates that he saw under the altar of God—that is, under the earth—the souls of those who were slain. For both heaven and earth are called God’s altar. This was shown in the Law, commanding that two altars be made, symbolizing the realities. . . . By the testimony that our Lord bears to it, we perceive that the golden altar is therefore called heaven. For he says, “When you bring your gift to the altar and there remember that your brother has something against you, leave your gift there before the altar.” Assuredly, our gifts are the prayers that we offer, and certainly our prayers ascend to heaven. Victorinus (c. 280, W), 7.351.
No one worships [at] the holy altar except the one who confesses this faith. Victorinus (c. 280, W), 7.354.