Apparently the burnt offering was the ordinance practiced from the time of Adam (Moses 5:7). This same offering will be offered again in our dispensation by the sons of Levi in fulfillment of the prophecies of Malachi and John the Baptist, and the promise of Joseph Smith (Malachi 3:3-4; D&C 13; Teachings, pp. 172-73).
The fact that they offered “sacrifice and burnt offerings according to the law of Moses” does not necessarily imply the existence of the intricate system of sacrifice in the law of carnal commandments. (See commentary on 2 Nephi 5:10.)