Numbers 18:24-27

²⁴For the tenths of the children of Israel which they set apart before the Lord for a separation, I have given to the Levites for a possession; therefore have I said to them, Among the sons of Israel you shall not possess an inheritance.

²⁵And the Lord spake with Mosheh, saying:

²⁶Speak also to the Levites, and say to them, When you take from the sons of Israel the tenths which I have given you of theirs, you shall set apart from them a separation before the Lord, a tenth of the tenth.

²⁷And your separation shall be reckoned to you as the corn from the threshing-floor, and as the wine of the wine-press;