Numbers 18:12-15

12“I am also giving you the first of the produce they give the Lord: the best of all the olive oil and the best of the new wine and fresh grain.

13The first of all produce harvested in their land that they bring to the Lord is yours. Anyone in your household who is clean may eat it.

14“Anything in Israel that is claimed by the Lord is yours.

15Every firstborn male, human or animal, that is brought to the Lord is yours. But you must buy back every firstborn son and the firstborn male of any unclean animal.