Augustine turns to his adolescence and describes his sins of lust. At sixteen, he came home from school for a year while his father tried to raise money to send him to a better school in Carthage. Augustine was by then sexually mature, which made his father happy, but worried his mother, who cautioned him against committing fornication and adultery. Augustine scoffed at her advice and enjoyed boasting to his friends about his sexual exploits, even if he had to exaggerate for effect. His mother could have arranged a marriage for him to give him a legitimate outlet for his sexual urges, but she feared that marriage at that time would hurt his chances for a successful career.
Augustine's account of his sexual sins is one of the most famous features of the Confessions, and that account begins here in Book 2, as Augustine becomes a teenager. Augustine's attitude toward his sexual urges is always deeply problematic, and a reluctance to give up sex is one of the last, painful obstacles to his full conversion. Here, however, Augustine gives a typically nuanced analysis of his sexual sins. His initial impulse, to love and be loved in return, is a good one, but once again, his good impulses are misdirected toward bad ends. He is unable to distinguish between physical love, which satisfies only lust, and the spiritual love of friendship and companionship, which satisfies the heart and the mind. With psychological acuteness, he also observes that part of his impulse toward promiscuity involved bragging rights with his group of friends, who took just as much pleasure in telling stories about their exploits as in the acts themselves. Given Augustine's statement that he sometimes had to exaggerate so that he would not seem too innocent to his buddies, one has to wonder exactly how bad his behavior really was.
The attitude of the early church toward sexuality of any kind was extremely negative, and Augustine reflects this attitude as he quotes advice against sex and marriage from the letters of the Apostle Paul. Complete celibacy was held up as the highest goal for a Christian, and marriage was a less admirable alternative, suitable only for those who could not fully control their sexual impulses and, therefore, required a "legitimate" outlet for them. Even within marriage, sexual activity was to be reserved solely for the conception of children, and not enjoyed for its own sake. Augustine describes his time of promiscuity as a period of misery, in which his suffering was reflective of God's gentle correction, although at the time, Augustine was still too ignorant to understand it.
The reaction of Augustine's parents to his developing sexuality is telling: Patricius, although nominally a Christian catechumen at this point, is thrilled at the prospect of having a grandchild, and Patricius' delight at seeing evidence of his son's sexual maturity — while Augustine is naked in a public bath — seems more than a little crude. Monica offers pious motherly advice about chastity, but no more than this, even though she is aware of Augustine's behavior. Augustine is careful to point out that God was speaking to him through his mother, though as a typical teenager he shrugs off her warnings. However, Augustine laments that his parents both refused to rescue him from his sin by arranging a legitimate marriage for him. The reason was simple: Marriage to a country girl would have held him back from a brilliant career, where he could make a more socially advantageous marriage to an heiress. (In fact, Monica arranges just such a marriage for him in Book 6.)
The dynamics of Augustine's family life are on display in this section, as he speculates about his parents' wishes for him. Worldly ambition for Augustine (possibly their oldest son) seems to drive both parents' actions, but Augustine reserves his sternest disapproval for Patricius, apparently because Patricius shows no awareness that there is any "success" beyond the shallow rewards that the world can give. Augustine notes with irony that everyone praised his father for making so many financial sacrifices for Augustine's education, even though his father cared nothing about the vicious character such an education would develop. Augustine presents Monica as more scrupulous. She feels that a literary education will at least do no harm to Augustine's spiritual life, but she, too, is anxious to see her son succeed. Augustine praises his mother's piety and faith, but there is still a note of criticism as he reports on her failure to save him from his sexual sins by seeing him properly married.