The LORD is the Creator, and he brought the universe into being by his command (see Gen 1.3, 6, 9). The universe is spoken of as the heavens and all their host, that is, “the sun, moon, and stars” (Good News Translation). In the two parallel lines, the word of the LORD and the breath of his mouth mean “his command … his spoken word” (Good News Translation). As commentators point out, breath here is not “spirit” or “Spirit,” but means speaking. In some languages instrumental phrases require recasting as time clauses or as two distinct sentences; for example, “When the LORD commanded, he created the heavens” or “When the LORD created the heavens, he did this by commanding it.”

Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .