Numbers 18:25-32 - Instructions For The Levites
25 Then the LORD instructed Moses, 26 "Tell the descendants of Levi that when they receive tithes from the Israelis (the tithes that I've given you from them as an inheritance), you are to offer a tenth of it as a raised offering for the LORD. 27 Your raised offerings are to be accounted for you as though it were grain from threshing floors and full produce from wine vats. 28 You are to offer a raised offering to the LORD from all your tithes that you receive from the Israelis. Give Aaron the priest the raised offering of the LORD 29 out of all the most consecrated offerings that you receive, that is, all the raised offerings of the LORD, with all its best and the most holy parts of it.
30 Tell them that when they bring the best from it, as far as the descendants of Levi are concerned, it is to be considered like produce from the threshing floors and wine vats. 31 You and your household may eat it anywhere, because it's a reward to you in return for your services at the Tent of Meeting. 32 You won't sin by offering the best of it, and you are not to profane the sacred things of the Israelis, so that you won't die."