This is not a complete nor an exhaustive (or exhausting) review of definitions of rhetoric. What it will be is some definitions of rhetoric and some of my early thoughts on them.
Anonymous, The Principals of Letter Writing: “A written composition is setting-forth of some matter in writing, proceeding in a suitable order. Or, a written composition is a suitable and fitting treatment of some matter, adapted to the matter itself. Or, a written composition is a suitable and fitting written statement about something, either memorized or declared by speech or in writing” (431).
Rhetoric, for me, is most often written, though classical rhetoric came out of a time of orality and the discipline of communication continues to develop their theories of oral rhetoric.
I think what applies most about this description is the suitable and fitting. Rhetoric, good rhetoric, ought to be applicable.
I also think that the idea of organization–a suitable order–is important. While organization is not the be-all and end-all, organization certainly impacts understanding, believability, and acceptance.
Augustine: “There are two things upon which every treatment of the Scriptures depends: the means of discovering what the thought may be, and the means of expressing what the thought is” (386).
Rhetoric provides one means of discovering what the Bible says and it is essential for expressing what the Bible says. Both the Scripture and meditations on the Bible are rhetorically grounded.