Broadus explains that a sermon to be good, to be effective must be “eloquent”. At this we must be careful: Eloquence does not mean rhetorically complex or “sophisticated.” Rather, eloquence creates change: an eloquent sermon moves the hearer:
Eloquence is so speaking as not merely to convince the judgment, kindle the imagination and move the feelings, but to give a powerful impulse to the will. All of these are necessary elements of eloquence, but that which is most characteristic is the last. There may be instruction and conviction without eloquence. The fancy may be charmed, as by a poem or novel, when you would not think of calling it eloquence. The feelings may be deeply stirred by a pathetic tale or a harrowing description, but no corresponding action being proposed, we do not speak of it as eloquence.
TPDS, 5. Eloquence, thus, only appears in the effect. An eloquent sermon does something. In this, Broadus runs in Baxter dictum, Preach as a dying man to dying men. There must be a desperation in the sermon to save, to transform.
Broadus next notes that eloquence derives from that most plain and common. Although he does not examine the point, I think it fair to note that only those things which touch near our skin have the power to transform — distant, abstract matters cannot stir the emotions.
Politicians manipulatively speak of “mothers” or “apple pie” or “kitchen tables” or more recently the human body as a point of political dispute. It is difficult to get most people to care about bond yields, but they will care about death and pain.
The sermon must concern itself with such commonplace matters or it will not move, and thus it will not be eloquent:
“What is the true ground of eloquence,” says Vinet, “if it is not commonplace? When eloquence is combined with high philosophical considerations, as in many modern examples, we are at first tempted to attribute to philosophy the impression we receive from it; but eloquence is something more popular; it is the power of making the primitive chords of the soul (its purely human elements) vibrate within us—it is in this, and nothing else, that we acknowledge the orator.”2 It is impossible to be eloquent on any subject, save by associating it with such ideas as that of mother, child, friends, home, country, heaven, and the like; all of them familiar, and, in themselves, commonplace. The speaker’s task is, by his grouping, illustration, etc., and by his own contagious emotion, to invest these familiar ideas with fresh interest, so that they may reassert their power over the hearts of his hearers.
TPDS, 7. What commonplace must occupy the center of the sermon:
The preacher can be really eloquent only when he speaks of those vital gospel truths which have necessarily become familiar. A just rhetoric, if there were no higher consideration, would require that a preacher shall preach the gospel—shall hold on to the old truths, and labor to clothe them with new interest and power.