To understand Irenaeus’ position on the rapture, we must first discuss a few items.
Scripture tells us that God promised Abraham and his seed two things: the inheritance of all the land of Israel (literally) (Genesis 13:14-15) and that the nations of the earth will be blessed (spiritually) (Genesis 12:2-3, Genesis 22:15-18). The former has not been fulfilled, the latter has been fulfilled in part. Abraham did not receive the inheritance of the land during his lifetime, but the nations of the earth have been blessed in that Christ has come and secured salvation for those of His children who have already repented and believed.
Since the whole of the land (and the earth) is yet to be inherited by Abraham and his seed, we need to know when this will occur and to whom it refers. Irenaeus says Abraham’s seed is ‘those who fear God and believe in Him.’ (Against Heresies, Book V, Chapter 32.2) This is one seed. Irenaeus does not separate Jewish believers from Gentile believers. Neither does the Apostle Paul (Ephesians 3:6). Thus, Abraham along with all believers will receive the inheritance of the land at the same time. Irenaeus says they will receive it at ‘the resurrection of the just.’ (Against Heresies, Book V, Ch 32.2, Ch 34.2, 34.3, Ch 36.3) This leaves us asking, when is the resurrection of the just?
Irenaeus refers to Revelation 20:4b-6a which says, “They came to life and reigned with Christ a thousand years. 5 (The rest of the dead did not come to life until the thousand years were ended.) This is the first resurrection. 6 Blessed and holy are those who share in the first resurrection.” The resurrection of the just is the first resurrection. When is this? Notice what it says after they come to life. They “reigned with Christ a thousand years.” How can the righteous reign with Christ? This must be because Christ has returned!
Does this lend to a “pre-tribulation rapture”? Again, notice the sequence. All believers will be resurrected at the same time, the first resurrection, and share in the inheritance of the land. This takes place at the Second Coming of Jesus Christ which occurs at the end of this present evil age and before the reign of Christ. For there to be a “rapture and (first) second coming” at the beginning of the tribulation there would have to be a “(first) first resurrection of the just” at the same time. This just is not the case. What is now popular pre-tribulation rapture teaching did not come into the church until the early 1800’s (through J.N. Darby).
Unfortunately, some think Irenaeus believed in a pre-tribulation rapture when he says, “the Church shall be suddenly caught up from this” (Against Heresies, Book V, Chapter 29.1). But he is not talking about the church being removed from the earth before the Tribulation. Look what he says next, “for this is the last contest of the righteous, in which, when they overcome they are crowned with incorruption.” It is when they overcome, after all the turmoil of the tribulation, they (the righteous) will be “caught up.” They will meet Jesus in the air. This is at Christ’s Second Coming! (1 Thessalonians 4:15-17) It is after the Tribulation, which they have just endured, that they will be crowned with their eternal reward.
(Notice that Irenaeus doesn’t refer to a particular set of saints who are saved during the Tribulation. He just says “the Church.” Other indicators in Irenaeus’ writings would confirm a post-tribulation rapture if one is interested in digging further!)
This should not be surprising to us. “Overcoming” was an ongoing theme for the early church. Why should the church at the end of the age have it any different? In fact, “overcoming” is still prominent in the book of Revelation (Rev. 2 & 3, Rev. 12:11, 13:7, 21:7).
So now we can answer when will the rapture of the church occur. It occurs at the resurrection of the just. That is, when Christ comes at the end of this present evil age, after the reign of the Antichrist and after the tribulation, not before.
For more information on this topic: Is the Rapture of the Church found in Revelation 4?