Charles Ellicott Commentary Psalms 19:2

"Day unto day uttereth speech, And night unto night showeth knowledge." — Psalms 19:2 (ASV)

Utters. —Literally, pours out, or makes well up, like a fountain, undoubtedly in reference to the light streaming forth.

Shows. —Literally, breathes out; perhaps with reference to the cool evening breeze, so welcome in the East. (See Song of Solomon 2:17, Note.) Notice that it is not here the heavens that are telling the tale of God’s glory to man, or “to the listening earth,” as in Addison’s well-known hymn, but day tells its successor day, and night whispers to night, so handing on, as if from parent to son, the great news.