Let me finish the previous point and post.
As I stated, it is not unusual for those who teach homiletics and its practitioners to shy away from employing rhetorical concepts in the preparation and delivery of the sermon. The word “rhetoric” has a negative connotation among preachers today. “Rhetoric” is something that is best kept at a distance from preaching. It is thought of as “linguistic manipulation” and found in the field of politics, not ministry!
The five “canons” of rhetoric are “invention,” “style,” “arrangement,” “memory,” and “delivery.”
The most challenged of those five canons are . . . .
“Invention”  — Preaching does not need to come up with material. We have already been given our content / material, the Word of God.
“Style” — Or as the classics might call it, “eloquence.” We do not come with eloquence, but with the plain truth. “Eloquence” is for the “sophist,” not the preacher.
“Memory,”  “Arrangement,” and “Delivery” are usually left untouched and little debated. That is why a typical homiletics class is much like “Fundamentals of Speech 101,” but with a Bible passage as the selected subject.
A second reaction to “rhetorical theory” centers around philosophical or ontological issues — How do we know truth? Preachers already have the “truth.” Other speakers who employ who engage in the art of public address do not begin with such an authoritative source. In law, politics (in the best sense of the word), or “sales,” the task is to convince, to persuade. In preaching, there is no question as to the truth of the Scriptures. That is why some say . . . .
“I’m not here to persuade you.”
“My job is to lay out the truth of God’s Word!”
“I didn’t write it. You will have to argue with God!”
As in the realm of “science,” the task is to lay out the truth. The sun is known to be 183 million miles away, and it takes approximately 8 minutes for light to leave the surface of the Sun and arrive on planet earth. That is a “scientific fact” — not something to be argued or involving the art of persuasion!
Light travels at 196 thousand miles a second!
I’m not here to persuade you of that.
I am telling you what is known truth!
However, when truth cannot be known — i.e. such as in the typical criminal setting of a courtroom — the speakers must now make the argument as to what has happened. What is the truth? That is now the realm of “argument” and persuasion.
The “truth” is not known. The “truth” of what has happened is argued, explained, testified to, questioned, answered, rebutted, cross-examined, supported by evidence, reasoned, time-lined, scientifically established by experts in the field, etc. At the end, what seems most right and reasonable is arrived at and is declared to be the “truth” by 12 jurors. If they do not believe it to be the “truth of the matter,” then they ought to and must acquit!
That method for arriving at the truth of a matter is biblical. That is why the Scriptures state — “He that is first in his own cause seemeth just; but his neighbour cometh and searcheth him.” Such as when you question your child as to who broke that vase and how did it happen.
When conclusive proof cannot be provided, or what seems to be factual or evident is up for dispute, then “argument” is the tool that is used to determine “the truth.” “Rhetoric” is the tool for arriving at the “truth of a matter.”
All of us have argued out a matter with others. The aim was to establish what had happened, must have happened, obviously happened, most likely happened, could not have happened — or what we should do, or what we should not do. Those arguments are typically not about what we know to be the truth (i.e. Is it okay to / Should we go to the bank and steal the money?). It is about what is unknown — should we take this-or-that job, marry this-or-that person, initiate this-or-that ministry program, dismiss or hire this-or-that person, etc.
However, that is not the case with a sermon. A preacher begins with “the truth.” The preacher’s task is not to determine what the truth is or to persuade them of its truth. 
Yet, because we begin with “the truth,” it does not change the rhetorical demands of making that truth speak to the minds and hearts of those listening. We wouldn’t have to preach if those listening were already in line with and living out that truth. The problem is not merely that this-or-that person does not know what the Bible says. It is that they know what it says but do not live it out!
If the task were the mere relating what the Bible says, then an “Amplified Bible” might be all that is needed. Those listening just need to have a clearly worded copy of what the passage is actually saying in the English language. The focus would then be on making sure that we provide a solid translation of the Scriptures. “Wycliffe Bible Translators” are then the means and hope for change, not effective Bible preachers.
However, that is not the case. Rather, it is by clearly and effectively preaching the truths of Scripture that lives are changed. It is the task of a preacher to determine how best to drive home the truth in a way that it is clear, effective, affective, and applicational.
That is also why every preacher is the same, yet different, when it comes to preaching and teaching the same Scripture passages! They are the same in that many of the same points are made. They are different because there are different ways to rhetorically make the argument of the passage. There are individual ways to make the points which the Scriptural passage is making. Some methods of framing, wording, clarifying, illustrating, explaining, structuring, describing, motivating, pushing, stating, exhorting are more effective — and some are less — and some are mediocre-to-terrible!
What’s the difference between preachers?
And it is an ability which increasingly gives the preacher a more effective platform for influencing the lives of others over time, rhetorical experience, and rhetorical understanding.
That is exactly the point! One can learn, and learns how to best communicate biblical truths.
1. The canon of “Invention” is not about pulling ideas out of a hat, or inventing material out of thin air. Rather, it is about thinking through options, ways of approaching, different methods for organizing, possible means of illustrating, thinking about ways to word something which sticks, considering the best way to make a point, etc.
2. The canon of “Memory” is totally unrelated to the “memorization” of the message or preaching without notes. The canon of “memoria” is about a speakers long-term recall of ideas, illustrations, wording, examples, quips, quotes, metaphors, outlines, passage break downs, cross-references, etc. which can be used in a speech or message. “Memoria” is what marks a preacher with years of experience under his belt. He is able to stand up and speak, off the cuff, at a graveside ceremony, with little to no immediate preparation. He has spoken and preached for so many years that he has developed a long-term mental storage file of various ideas and thoughts.
3. Although that is also the task many more times than we realize!
For example . . . .
- 3. Although that is also the task many more times than we realize!
For example . . . .
- when a preacher says that the Scriptures were written over 1400 years, by various authors, producing 66 books, and they all agree as to who the God of this world is.
- when a preacher talks about the hundreds of prophecies about the coming Messiah , which all found fulfillment in Jesus.
- when the author of a book is in question.
- when a particular understanding of a passage or biblical event differs from that of others — i.e. Good Friday or Good Thursday?
- when a preacher seeks to persuade an audience that the best understanding of this-or-that passage is . . . .
- when application is made — as to what the truth of this verse looks like in our lives.
- when preachers connect the truths of Scripture and make the argument that this verse is understood by realizing another verse or passage.
- or when
- or when.