In a very interesting book on the debate as to whether Christ’s human nature was fallen or not, E. Jerome Van Kuiken wrote the following about Irenaeus’ approach to this particular issue vis-à-vis Christ truly suffering and dying:
Christ’s flesh and death
Yet if Christ’s flesh is free from all guilt and sin, how can he experience their consequences, suffering and death? Irenaeus explains:
Indeed, just as He was man that He might undergo temptation, so He was the Word that e might be glorified. The Word, on the one hand, remained quiescent [requiescente/ησυχαζοντος], that He could be tempted and dishonored and crucified and die; on the other hand, the man was absorbed [absorto], that He might conquer and endure the show Himself kind, and rise again and be taken up [into heaven] (Against Heresies, 3.19.3).
As previously noted, Irenaeus’ anthropology allows that human flesh is inherently capable of passion and death. He sees the Logos as passive enough to allow temptation, suffering and death to touch his human weakness, yet active enough to overcome them and to grant life both to others and to his own human nature. Throughout Jesus’ life—whether in his birth, baptism, resistance to temptation, healings, or resurrection—human sin, corruption, and death were being ‘absorbed’ or ‘swallowed up’ by the divine victory of incorruption and immortality (1 Cor. 15.54).
Inasmuch as the Logos, through voluntary restraint of his divine influence over his flesh, suffers the physical effects of the Fall, Irenaeus applies the term ‘fallen’ (πεπτωκυιαν) to Christ’s flesh when speaking of its mortality: ‘And He demonstrated the resurrection, becoming Himself “the firstborn from the dead”, and raising in Himself fallen [“deictum (πιπτω)”] man . . . a God had promised, by the prophets, saying, “I will raise up the fallen [‘deictum (πιπτω)’] tabernacle of David”, [Amos 9:11/Acts 15:16] that is, the flesh [descended] from David.’
In relation to sin, however, Christ maintains an unfallen state throughout his life. Irenaeus notes that in tempting Jesus to false worship, Satan urges him to ‘fall’ (Mt. 4.9). Irenaeus sees the word as an admission that to serve Satan is to ‘fall’ from God’s glory to the verge of death. Unlike Adam and all other humans, Christ refuses this temptation (Against Heresies, 5.22.2-32.1). Rather than falling into sin, the Son comes ‘stooping low [descendens/καταβας] even to death’ (Against Heresies, 3.18.2) as a Saviour from sin and death. (E. Jerome Van Kuiken, Christ’s Humanity in Current and Ancient Controversy: Fallen or Not? [London: T&T Clark, 2017, 2019], 102-4)
