Numbers 31:29 WEB

²⁷  and divide the prey into two parts: between the men skilled in war, who went out to battle, and all the congregation.

²⁸  Levy a tribute to Yahweh of the men of war who went out to battle: one soul of five hundred, [both] of the persons, and of the oxen, and of the donkeys, and of the flocks:

²⁹  take it of their half, and give it to Eleazar the priest, for Yahweh's heave-offering.

³⁰  Of the children of Israel's half, you shall take one drawn out of every fifty, of the persons, of the oxen, of the donkeys, and of the flocks, [even] of all the cattle, and give them to the Levites, who keep the charge of the tent of Yahweh.

³¹  Moses and Eleazar the priest did as Yahweh commanded Moses.