Book 4 of 4 - External Means by which God Invites Us into the Society of Christ and Holds Us Therein
Chapter 13 - Rash vows and their entanglements
8-10 - Monastic vows; decline of monastic life
8. Monasteries in ancient times had great discipline, and supplied clergy for the church.
9. Augustine depicts monastic life's severity as tempered by love and sensitivity for one another.
10. Unlike back then, today's monasteries require what Scripture doesn't even mention. "They dream up some new sort of piety."
11-14 - The fallacy of monastic perfection
11. Monks claim perfection, when recruiting among the common folk. When pressed, they say they are closest to it. "All other callings of God are regarded as unworthy by comparison."
12. They say monks have a greater obligation to obey Christ's commands (not to swear or seek vengeance, to love enemies, etc). But all "men must... obey every little word uttered by Christ."
13. Matt 19:21 says "If you wish to be perfect, sell all you have and give to the poor." But Jesus said this "to teach [the rich young ruler] how little he had advanced toward that righteousness which he too boldly replied he had fulfilled." He points out his imperfection, more than showing him the way to perfection. Jesus was not recommending voluntary poverty as a way of life.
14. They blasphemously compare monasticism to baptism. Today's monks separate completely from the church, setting up their own worship, sacraments, fellowship. They are a "conventicle of schismatics."