Numbers 16:40

16:40 It was a memorial for the Israelites, that no outsider who is not a descendant of Aaron should approach to burn incense before the Lord, that he might not become like Korah and his company – just as the Lord had spoken by the authority of Moses.

Numbers 18:17

18:17 But you must not redeem the firstborn of a cow or a sheep or a goat; they are holy. You must splash their blood on the altar and burn their fat for an offering made by fire for a pleasing aroma to the Lord.