Numbers 18:12-18, 27-30

“I give you all the finest olive oil and all the finest new wine and grain they give the LORD as the firstfruits of their harvest. All the land’s firstfruits that they bring to the LORD will be yours. Everyone in your household who is ceremonially clean may eat it. “Everything in Israel that is devoted to the LORD is yours. The first offspring of every womb, both human and animal, that is offered to the LORD is yours. But you must redeem every firstborn son and every firstborn male of unclean animals. When they are a month old, you must redeem them at the redemption price set at five shekels of silver, according to the sanctuary shekel, which weighs twenty gerahs. “But you must not redeem the firstborn of a cow, a sheep or a goat; they are holy. Splash their blood against the altar and burn their fat as a food offering, an aroma pleasing to the LORD. Their meat is to be yours, just as the breast of the wave offering and the right thigh are yours.

Your offering will be reckoned to you as grain from the threshing floor or juice from the winepress. In this way you also will present an offering to the LORD from all the tithes you receive from the Israelites. From these tithes you must give the LORD’s portion to Aaron the priest. You must present as the LORD’s portion the best and holiest part of everything given to you.’ “Say to the Levites: ‘When you present the best part, it will be reckoned to you as the product of the threshing floor or the winepress.