Numbers 18:25–32

²⁵The Lord said to Moses, ²⁶“Speak to the Levites and say to them: You will take one-tenth of the Israelites’ income which I’m giving you as your property. When you do, you must contribute one-tenth of that income as your contribution to the Lord. ²⁷Your contribution will be considered to be grain from the threshing floor^bor juice from the winepress. ²⁸So you, too, will contribute one-tenth of your income to the Lord out of all that you receive from the Israelites’ income. You will give the Lord’s contribution to the priest Aaron. ²⁹Out of all the gifts you receive, you must contribute the best and holiest parts to the Lord. 

³⁰“Also tell them: When you contribute the best part, your contribution will be considered to be produce from the threshing floor or winepress. ³¹So you and your households may eat it anywhere, because it’s the wages you receive for your work at the tent of meeting. ³²When you contribute the best part, you won’t suffer the consequences of any sin. You won’t be dishonoring the holy offerings given by the Israelites, and you won’t die.”