Numbers 18
24 Ref For the tenths which the children of Israel give as a lifted offering to the Lord I have given to the Levites as their heritage. and so I have said to them, Among the children of Israel they will have no heritage.
25 And the Lord said to Moses,
26 Ref Say to the Levites, When you take from the children of Israel the tenth which I have given to you from them as your heritage, a tenth part of that tenth is to be offered as an offering lifted up before the Lord.