By the word of Yahweh the heavens were made

This can be stated in active form. AT: "By using his word, Yahweh made the heavens" (See: rc://en/ta/man/translate/figs-activepassive)

by the breath of his mouth

This refers to Yahweh's word. AT: "by his word" (See: rc://en/ta/man/translate/figs-metonymy)