Here is, 1. The great use for which the word of God was intended, to give light, that is, to give understanding, to give us to understand that which will be of use to us in our travels through this world; and it is the outward and ordinary means by which the Spirit of God enlightens the understanding of all that are sanctified. God's testimonies are not only wonderful for the greatness of them, but useful, as a light in a dark place. 2. Its efficacy for this purpose. It admirably answers the end; for, (1.) Even the entrance of God's word gives light. If we begin at the beginning, and take it before us, we shall find that the very first verses of the Bible give us surprising and yet satisfying discoveries of the origin of the universe, about which, without that, the world is utterly in the dark. As soon as the word of God enters into us, and has a place in us, it enlightens us; we find we begin to see when we begin to study the word of God. The very first principles of the oracles of God, the plainest truths, the milk appointed for the babes, bring a great light into the soul, much more will the soul be illuminated by the sublime mysteries that are found there. "The exposition or explication of thy word gives light;" then it is most profitable when ministers do their part in giving the sense, Neh 8:8. Some understand it of the New Testament, which is the opening or unfolding of the Old, which would give light concerning life and immortality. (2.) It would give understanding even to the simple, to the weakest capacities; for it shows us a way to heaven so plain that the wayfaring men, though fools, shall not err therein.