On Christian Oratory?

So when only two people in classed raised their hands as having read Augustine before, I was shocked. I read him in every class I ever took in medieval studies (but I suppose I never read him in any other classes). Confessions was one of the first things I read in college. I can't say On Free Will or City of God did quite as much for me although they were still interesting. But I'd never read On Christian Doctrine before, at least not the excerpt we read for class, so I was surprised at how much Augustine, the Christian philosopher, had to say about rhetoric.

Augustine has a lot of good advice when it comes to eloquence: content matters ("those who speak with wisdom are heard with profit" 459), don't go overboard with a incessantly grand style (478), and models of are more useful than rules (457). But when I try to examine Augustine's view of rhetoric, I'm drawn back to the title. On Christian Doctrine. And doctrine may not really be the best word here, even if it does look more like the Latin doctrina than the English teaching. The book was not called On Christian Oratory, and certainly not On Oratory. So how sure can I be that this is the extent of rhetoric for Augustine? Has he merely narrowed his scope to talk about the relevance of rhetoric to Christian teaching? Perhaps political speeches weren't common in his day, but what about courts?

I know Augustine is aware of courts, because he talks about them in City of God, which I don't even have a copy of to cite. I can't help wondering what Augustine might have said in On Christian Oratory. Would he still have said that Christian oratory is for instruction and persuasion in Christian doctrine? That although we sometimes find ourselves in legal trouble, we shouldn't spend too much time on these worldly concerns? I'd like to imagine that he would see a place for even Christian lawyers, but I don't think he would, as disillusioned as he was with the world.

Work Cited
Augustine. On Christian Doctrine. Trans. Therese Sullivan. The Rhetorical Tradition: Readings from Classical Times to the Present. Ed. Patricia Bizzell and Bruce Herzberg. Boston: Bedford/St. Martins, 2001. 456-485.