Exodus 30:17

15The rich shall not give more, and the poor shall not give less, than the half shekel, when they give the offering of the LORD, to make atonement for your souls.

16You shall take the atonement money from the children of Israel, and shall appoint it for the service of the Tent of Meeting; that it may be a memorial for the children of Israel before the LORD, to make atonement for your souls.”

17The LORD spoke to Moses, saying,

18“You shall also make a basin of bronze, and its base of bronze, in which to wash. You shall put it between the Tent of Meeting and the altar, and you shall put water in it.

19Aaron and his sons shall wash their hands and their feet in it.