St. Gregory the Theologian, Oration 38, Section 12:
This being was placed in paradise, whatever that paradise was then, honored with self-determination so that the good would belong to the one who chose it no less than to the one who provided its seeds. The human being was a cultivator of immortal plants, that is perhaps divine thoughts, both simpler and the more complete. He was naked because of his simplicity and life free from artifice and far from any covering or screen, for such a condition befitted the one who existed at the beginning. God gave him a law as material on which his self-determination could work, and the law was a commandment indicating which plants he could possess and which one he was not to touch. And that was the tree of knowledge, which was neither planted from the beginning in an evil way nor forbidden through envy — let the enemies of God not wag their tongues in that direction, nor imitate the serpent — but would be good if possessed at the right time. For the tree is contemplation, according to my own contemplation, which is only safe for those of mature disposition to undertake; but it is not good for those who are still simpler and those greedy in their desire, just as adult food is not useful for those who are still tender and in need of milk. But after the devil’s envy and the woman’s spiteful treatment, both what she underwent as more tender and what she set before the man as more persuasive — alas for my weakness, for that of the first father is mine! — he forgot the commandment given him and yielded to the bitter taste. And at once he came to be banished from the tree of life and from paradise and from God because of the evil, and was clothed in tunics of skin, that is perhaps the more coarse and mortal and rebellious flesh, and for the first time he knew his own shame and hid from God. He gained a certain advantage from this; death is also the cutting off of sin, that evil might not be immortal, so the punishment becomes love for humankind. For thus, I am persuaded, God punishes.