Why did it bring death to humanity to eat of the fruit of the Tree of the knowledge of good and evil?
Eating from the tree was a sacramental act: it severed the state of communion with God and united man to a different spiritual condition.
The act involved disobedience to God’s will, and so separated man from God and his grace, alienating him from the life of God and issuing in dis-integration, death. As St Irenaeus wrote: “Fellowship with God is light and life… separation from God is death” (St Irenaeus, Against Heresies, V.27.2; see Q024, Q090). The same Father reveals the mercy hidden even in the expulsion from Paradise:
God showed a gentle mercy toward the one who had been seduced… he cast man out of Paradise and removed him far from the tree of life because he pitied him, lest he continue in transgression forever and the evil be without end or remedy. So he put a stop to wickedness by interposing death, making sin to cease… so that man, by dying to sin, should begin to live to God. (St Irenaeus, Against Heresies, III.23.6)
Death itself, in God’s providence, becomes a severe mercy, the sealing off of endless evil, and the door through which Christ will enter to destroy it.
