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. To every preacher of righteousness as well as to Noah, wisdom gives the command, "A window shalt thou make in the ark." You may build up laborious definitions and explanations and yet leave your hearers in the dark as to your meaning; but a thoroughly suitable metaphor will wonderfully clear the sense. The pictures in an illustrated paper give us a far better idea of the scenery which they represent than could be conveyed to us by the best descriptive letterpress; and it is much the same with scriptural teaching: abstract truth comes before us so much more vividly when a concrete example is given, or the doctrine itself is clothed in figurative language. There should, if possible, be at least one good metaphor in the shortest address; as Ezekiel, in his vision of the temple, saw that even to the little chambers there were windows suitable to their size. If we are faithful to the spirit of the gospel we labor to make things plain: it is our study to be simple and to be understood by the most illiterate of our hearers; let us, then, set forth many a metaphor and parable before the people. He wrote wisely who said, "The world below me is a glass in which I may see the world above. The works of God are the shepherd's calendar and the plowman's alphabet." Having nothing to conceal, we have no ambition to be obscure. Lycophron declared that he would hang himself upon a tree if he found a person who could understand his poem entitled "The Prophecy of Cassandra." Happily no one arose to drive him to such a misuse of timber. We think we could find brethren in the ministry who might safely run the same risk in connection with their sermons. Still have we among us those who are like Heraclitus, who was called "the Dark Doctor" because his language was beyond all comprehension. Certain mystical discourses are so dense that if light were admitted into them it would be extinguished like a torch in the Grotta del Cane: they are made up of the palpably obscure and the inexplicably involved, and all hope of understanding them may be abandoned. This style of oratory we do not cultivate. We are of the same mind as Joshua Shute, who said: "That sermon has most learning in it that has most plainness. Hence it is that a great scholar was wont to