Numbers 18:13

10 As most holy things they are to be your food: let every male have them for food; it is to be holy to you.

11 And this is yours: the lifted offering which they give and all the wave offerings of the children of Israel I have given to you and to your sons and to your daughters as your right for ever: everyone in your house who is clean may have them for food.

12 All the best of the oil and the wine and the grain, the first-fruits of them which they give to the Lord, to you have I given them.

13 The earliest produce from their land which they take to the Lord is to be yours; everyone in your house who is clean may have it for his food.

14 Everything given by oath to the Lord in Israel is to be yours.

15 The first birth of every living thing which is offered to the Lord, of man or beast, is to be yours; but for the first sons of man payment is to be made, and for the first young of unclean beasts.

16 Payment is to be made for these when they are a month old, at the value fixed by you, a price of five shekels by the scale of the holy place, that is, twenty gerahs to the shekel.