On the Creation of the World (151-152)

But since nothing in creation lasts for ever, but all mortal things are liable to inevitable changes and alterations, it was unavoidable that the first man should also undergo some disaster. And the beginning of his life being liable to reproach, was his wife. For, as long as he was single, he resembled, as to his creation, both the world and God; and he represented in his soul the characteristics of the nature of each, I do not mean all of them, but such as a mortal constitution was capable of admitting. But when woman also was created, man perceiving a closely connected figure and a kindred formation to his own, rejoiced at the sight, and approached her and embraced her.

And she, in like manner, beholding a creature greatly resembling herself, rejoiced also, and addressed him in reply with due modesty. And love being engendered, and, as it were, uniting two separate portions of one animal into one body, adapted them to each other, implanting in each of them a desire of connection with the other with a view to the generation of a being similar to themselves. And this desire caused likewise pleasure to their bodies, which is the beginning of iniquities and transgressions, and it is owing to this that men have exchanged their previously immortal and happy existence for one which is mortal and full of misfortune.