The phrase "the scroll of Yahweh" means that it contains the messages spoken by Yahweh. Alternate translation: "Read carefully what is written in this scroll that contains the messages of Yahweh" (See: [[rc://en/ta/man/translate/figs-possession]])
Yahweh is referred to by his "mouth" to emphasize what he has said. Alternate translation: "for Yahweh has commanded it" (See: [[rc://en/ta/man/translate/figs-synecdoche]])