Day unto day; or rather, after (as the Hebrew lamed oft signifies, as Exodus 16:1, Exodus 29:38 2 Chronicles 30:21 Psalms 96:2) day; for the day doth not utter this to the day, but to us upon the day. The sense is either,
1. That orderly, and constant, and useful succession of days and nights one after another declare this. But of the course of the sun, the effect whereof this succession is, he speaks Psalms 19:5. Or rather,
2. Every day and night renews or repeats these documents and demonstrations of God's glory. He that neglects them one day, may learn them the next day. Uttereth, or, poureth forth, to wit, constantly, and abundantly, and forcibly, as a fountain doth water, as this Hebrew verb signifies. Speech; or the word, or discourse, to wit, concerning God. It hath as it were a tongue to speak the praises of its Maker, i.e. it gives men occasion to magnify and adore him. Showeth knowledge, i. e. gives us a clear and certain knowledge or discovery of God their author.