The topic now before us is the use of illustrations in our sermons. Perhaps we shall best subserve our purpose by working out an illustration in the present address; for there is no better way of teaching the art of pottery than by making a pot. Quaint Thomas Fuller says, "Reasons are the pillars of the fabric of a sermon; but similitudes are the windows which give the best lights." The comparison is happy and suggestive, and we will build up our discourse under its direction.
The chief reason for the construction of windows in a house is, as Fuller says, to let in light. Parables, similes, and metaphors have that effect; and hence we use them to illustrate our subject, or, in other words, to "brighten it with light," for that is Dr. Johnson's literal rendering of the word illustrate. Often when didactic speech fails to enlighten our hearers we may make them see our meaning by opening a window and letting in the pleasant light of analogy. Our Saviour, who is the light of the world, took care to fill his speech with similitudes, so that the common people heard him gladly; his example stamps with high authority the practice of illuminating heavenly instruction with comparisons and similes.