Scriptures:
Genesis 5:24 – “Enoch pleased God, and he was not found, because God translated him.”
1 Kings 17:1 – “And Elijah the Tishbite said to Ahab, ‘As the Lord God of Israel lives, before whom I stand, there shall be neither dew nor rain these years, except by my word.’”
2 Kings 2:11 – “As they were walking and talking, a chariot of fire and horses of fire appeared and separated the two of them, and Elijah went up to heaven in a whirlwind.”
Luke 4:25 – “There were many widows in Israel in Elijah’s time, when the sky was shut for three and a half years and there was a severe famine.”
James 5:17 – “Elijah was a man just like us. He prayed earnestly that it would not rain, and it did not rain on the land for three and a half years.”
Malachi 4:5 – “Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord.”
Revelation 11:3–6 – “I will appoint my two witnesses, and they will prophesy for 1,260 days [three and a half years], clothed in sackcloth. These are the two olive trees and the two lampstands that stand before the Lord of the earth. If anyone tries to harm them, fire comes from their mouths and devours their enemies. They have power to shut up the heavens so that no rain falls during the days of their prophecy, and power to turn the waters into blood and to strike the earth with every kind of plague as often as they want.”
Revelation 11:7–12 – “When they finish their testimony, the beast will attack and kill them. Their bodies will lie in the street of Jerusalem for three and a half days. But after that, the breath of life from God will enter them, and they will rise to heaven in a cloud as their enemies watch.”
Church Fathers:
Tertullian:
Enoch no doubt was translated, and so was Elijah; nor did they experience death: it was postponed, most certainly: they are reserved for the suffering of death, that by their blood they may extinguish Antichrist. – Tertullian, A Treatise on the Soul chapter 50
Hippolytus:
For after sixty-two weeks was fulfilled and after Christ has come and the Gospel has been preached in every place, times having been spun out, the end remains one week away, in which Elijah and Enoch shall be present and in its half the abomination of desolation, the Antichrist, shall appear who threatens desolation of the world. After he comes, sacrifice and drink offering, which now in every way is offered by the nations to God, shall be taken away. — Hippolytus, Commentary on Daniel 4.35.3
Now Daniel will set forth this subject to us. For he says, And one week will make a covenant with many, and it shall be that in the midst (half) of the week my sacrifice and oblation shall cease. Daniel 9:27 By one week, therefore, he meant the last week which is to be at the end of the whole world of which week the two prophets Enoch and Elias will take up the half. For they will preach 1, 260 days clothed in sackcloth, proclaiming repentance to the people and to all the nations. – Hippolytus, On Christ and Antichrist
Origen:
However, it is likely that before the second and more divine coming of Christ, John or Elijah will come to bear witness about life. – Origen, Commentary on John, book 2, chapter 30
Victorinus:
2. “And I saw another angel ascending from the east, having the seal of the living God.” He speaks of Elias the prophet, who is the precursor of the times of Antichrist, for the restoration and establishment of the churches from the great and intolerable persecution. We read that these things are predicted in the opening of the Old and New Testament; for He says by Malachi: “Lo, I will send to you Elias the Tishbite, to turn the hearts of the fathers to the children, according to the time of calling, to recall the Jews to the faith of the people that succeed them.” And to that end He shows, as we have said, that the number of those that shall believe, of the Jews and of the nations, is a great multitude which no man was able to number. Moreover, we read in the Gospel that the prayers of the Church are sent from heaven by an angel, and that they are received against wrath, and that the kingdom of Antichrist is cast out and extinguished by holy angels; for He says: “Pray that you enter not into temptation: for there shall be a great affliction, such as has not been from the beginning of the world; and except the Lord had shortened those days, no flesh should be saved” (Mark 13:18-20). – Victorinus, Commentary on Revelation, from the seventh chapter
6. But the woman fled into the wilderness, and there were given to her two great eagle’s wings. The aid of the great eagle’s wings — to wit, the gift of prophets— was given to that Catholic Church, whence in the last times a hundred and forty-four thousands of men should believe in the preaching of Elias; but, moreover, he here says that the rest of the people should be found alive on the coming of the Lord. And the Lord says in the Gospel: Then let them which are in Judea flee to the mountains; Luke 21:21 that is, as many as should be gathered together in Judea, let them go to that place which they have ready, and let them be supported there for three years and six months from the presence of the devil. 14. Two great wings are the two prophets— Elias, and the prophet who shall be with him. – Victorinus, Commentary on Revelation, from the twelfth chapter
John Cassian:
Wherefore on those passages which are brought forward with a clear explanation we also can constantly lay down the meaning and boldly state our own opinions. But those which the Holy Spirit, reserving for our meditation and exercise, has inserted in holy Scripture with veiled meaning, wishing some of them to be gathered from various proofs and conjectures, ought to be step by step and carefully brought together, so that their assertions and proofs may be arranged by the discretion of the man who is arguing or supporting them. For sometimes when a difference of opinion is expressed on one and the same subject, either view may be considered reasonable and be held without injury to the faith either firmly, or doubtfully, i.e., in such a way that neither is full belief nor absolute rejection accorded to it, and the second view need not interfere with the former, if neither of them is found to be opposed to the faith: as in this case: where Elias came in the person of John, and is again to be the precursor of the Lord’s Advent: and in the matter of the “Abomination of desolation” which “stood in the holy place,” by means of that idol of Jupiter which, as we read, was placed in the temple in Jerusalem, and which is again to stand in the Church through the coming of Antichrist,and all those things which follow in the gospel, which we take as having been fulfilled before the captivity of Jerusalem and still to be fulfilled at the end of this world. In which matters neither view is opposed to the other, nor does the first interpretation interfere with the second. – John Cassian, Conferences, book 8, chapter 4