Leviticus 27:33

‘He shall not replace it or exchange it, a good for a bad, or a bad for a good; or if he does exchange animal for animal, then both it and its substitute shall become holy.

“Every devoted thing in Israel shall be yours.

“Now to the sons of Levi, behold, I have given all the tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting.

“They shall eat equal portions, except what they receive from the sale of their fathers’ estates.

“Moreover, they shall not sell or exchange any of it, or let this choice portion of land pass over to another; for it is holy to Yahweh.