Exodus 30:21
Their hands and feet are to be washed. so that they may be safe from death: this is an order to them for ever; to him and his seed from generation to generation.
Exodus 28:43
Aaron and his sons are to put these on whenever they go into the Tent of meeting or come near the altar, when they are doing the work of the holy place, so that they may be free from any sin causing death: this is to be an order for him and his seed after him for ever.
Exodus 27:21
Let Aaron and his sons put this in order, evening and morning, before the Lord, inside the Tent of meeting, outside the veil which is before the ark; this is to be an order for ever, from generation to generation, to be kept by the children of Israel.