These exist for the purpose of making clear the truths to be presented. Illustrations are like windows that let in the light; but these should not be too numerous, for one's sermon should not resemble a glass-house. A gospel address should not consist of an endless string of anecdotes, with a few odd texts interspersed to keep it from falling apart; but should be a setting forth of the truth of Scripture, for this alone can give authority to the message. The sermon does not exist for the sake of the illustrations but vice versa. These illustrations, though necessary, are purely incidental.
Henry Ward Beecher has pointed out that illustrations serve a sevenfold purpose.
They assist argument.
They help the hearer to remember.
They stimulate the imagination.
They rest the audience.
They provide for various classes of hearers.
They bridge difficult places.
They enforce the truth.—Alfred P. Gibbs
(Matt. 13. 3; Gal. 4. 24)
Let your illustrations be such as shine into your sermon, and not illustrations you drag in. You have heard men preach, and tell a story. The story has really no vital relationship with their message. They put it in, and it relieves the congregation, making them smile at the moment, perhaps, but it has no relation to the sermon. One of the most skilful in this matter that I have known was John Henry Jowett.—Dr. Jowett's illustrations always shone into his main theme. You never went away with the illustration as the supreme thing; it was there illuminating. I remember hearing him in Birmingham, when he said: `Human and Divine divisions of humanity are radically different. Divine divisions are perpendicular, human divisions are horizontal.' Well, there we were. He picked up his hymn book, held it upright, and said, `I will show you what I mean. That is perpendicular division to the right, to the left: that is Divine.' Then, holding it flat—`This is horizontal—upper, middle, lower classes: that is human.'—Dr. G. Campbell Morgan
Pat was set to work with the circular saw during his first day at the saw mill. The foreman gave careful instructions how to guard against injury, but no sooner was his back turned than he heard a howl from the novice, and, on turning, he saw that Pat had already lost a finger.
"Now, how did that happen?" the foreman demanded.
"Sure," was the explanation, "I was jist doin' like this when,—bejabers, there's another gone!"