“He shall not alter it, nor exchange it, a good for a bad, or a bad for a good. If he shall at all exchange animal for animal, then both it and that for which it is exchanged shall be holy.”
Leviticus 27:10 (WEB)
Context Reading
8But if he is poorer than your valuation, then he shall be set before the priest, and the priest shall assign a value to him. The priest shall assign a value according to his ability to pay. 9“‘If it is an animal of which men offer an offering to Yahweh, all that any man gives of such to Yahweh becomes holy. 10He shall not alter it, nor exchange it, a good for a bad, or a bad for a good. If he shall at all exchange animal for animal, then both it and that for which it is exchanged shall be holy. 11If it is any unclean animal, of which they do not offer as an offering to Yahweh, then he shall set the animal before the priest; 12and the priest shall evaluate it, whether it is good or bad. As the priest evaluates it, so it shall be.