It has already been stated that he killed these animals as a burnt offering. AT: "I have killed a bull and a ram and burnt them as an offering" (See: [[rc://en/ta/man/translate/figs-explicit]])
Here Yahweh giving Balaam a message to speak is spoken of as if Yahweh placed it in his mouth. AT: "Yahweh told Balaam what he wanted him to say to Balak" (See: [[rc://en/ta/man/translate/figs-metaphor]])