Ben Witherington, lecturing on the necessity of rhetorical criticism in NT interpretation:

So far as we can tell, no documents in antiquity were intended for silent reading, and only a few were intended for private individuals to read.  They were always meant to be read out loud, and usually read out loud to a group of people.  For the most part, they were simply necessary surrogates for oral communication.  This was particularly true of ancient letters.  In fact, most ancient documents, including letters, were not really “texts” at all in the modern sense of the word.  They were composed with their aural and oral potential in mind, and they were meant to be orally delivered when they arrived at their destination.

and later in the lecture:

. . . Paul saw his letters as just the surrogates for a speech he would have given them in person if he could only have been there.  Letters are just the literary residue of discourses with epistolary framework added because they have to be sent from a distance.

It is no mere rhetoric, full of sound and fury, and signifying very little, to say that analyzing the New Testament orally and rhetorically gets us back in touch with the original ethos and character of these documents.

(”Oral Texts and Rhetorical Letters: Rethinking the Categories,” Baylor University, Parchman Lectures, Lecture 1 [October 2, 2007]; online: http://www.baylortv.com/video.php?id=001319, where the lecture appears to be mislabeled “Canonical Pseudepigrapha: Is It an Oxymoron?”)

A similar point is made by, e.g., H. Van Dyke Parunak, “Oral Typesetting: Some Uses of Biblical Structure,” Biblica 62 (1981): 153-68; and John D. Harvey, Listening to the Text: Oral Patterning in Paul’s Letters (Grand Rapids: Baker, 1998).