Book Four of "De doctrina Christiana" has sparked a great deal of debate among scholars with regards to the extent to which Augustine's work has been influenced by the rules and traditions of classical rhetoric, and more specifically by the writings of Cicero. In the final chapter of On Christian Doctrine, Augustine uses much of Cicero's rhetorical theory as he lays down the foundation for the proper use of rhetoric by Christian teachers. For example, Augustine quotes Cicero (Orat. 21. 69.) when he writes, “a certain eloquent man said, and said truly, that he who is eloquent should speak in such a way that he teaches, delights, and moves.”