As the separation of the soul from the body is the death of the body, so the separation of God from the soul is the death of the soul. And this death of the soul is the true death. This is made clear by the commandment given in paradise, when God said to Adam, On whatever day you eat from the forbidden tree you will certainly die.’ And it was indeed Adam’s soul that died by becoming through his transgression separated from God; for bodily he continued to live after that time, even for nine hundred and thirty years. The death, however, that befell the soul because of the transgression not only crippled the soul and made man accursed; it also rendered the body itself subject to fatigue, suffering and corruptibility, and finally handed it over to death. For it was after the dying of his inner self brought about by the transgression that the earthly Adam heard the words, Earth will be cursed because of what you do, it will produce thorns and thistles for you.’ … Thus the violation of God’s commandment is the cause of all types of death, both of soul and body, whether in the present life or in that endless chastisement. And death, properly speaking, is this: for the soul to be unharnessed from divine grace and to be yoked to sin. This death, for those who have their wits, is truly dreadful and something to be avoided. This, for those who think aright, is more terrible than the chastisement of Gehenna. … As the death of the soul is authentic death, so the life of the soul is authentic life. Life of the soul is union with God, as life of the body is union with the soul. As the soul was separated from God and died in consequence of the violation of the commandment, so by obedience to the commandment it is again united to God and is quickened. … The death of the soul through transgression and sin, is then, followed by the death of the body and by its dissolution in the earth and its conversion into dust; and this bodily death is followed in its turn by the soul’s banishment to Hades. …
After our forefather’s transgression in paradise through the tree, we suffered the death of our soul—which is the separation of the soul from God—prior to our bodily death; yet although we cast away our divine likeness, we did not lose our divine image.
(“Topics on Natural and Theological Science”, Chapters 9-14, Philokalia 4:296-297, 363)