Augustine's full embrace of Christianity later in life includes adopting celibacy. From this celibate vantagepoint, Augustine examines the sources for the decidedly un-celibate behavior as a younger man that he has described in his Confessions. He identifies two closely related causes.
The first cause he gives is weakness, which seems simple enough except that it carries overtones of Neoplatonism. He says that, through a weakness of will, he turned away from God and truth and toward the "lower" realms of creation (as set out in Augustine's blended Neoplatonic-Christian worldview). This is the realm of base, sensory matter, of time, of flux, and of multiplicity—all of which distract us from God. Plato called this realm the “region of dissimilarity” (a quote Augustine uses) to denote its distance from the pure, heavenly forms that represent the perfect models for each thing.
Augustine then adds that he was seeking only love in all his lustful trysts. This account refers to the presence of God in all things, no matter how low in the hierarchy of Being—since God is the constant cause of the existence of all these things—they all yearn to be with God whether they know it or not. Therefore, Augustine, though turned away from God toward lower things, cannot escape the desire to be like Him.