Exodus 27:21

27:21 In the tent of meeting outside the curtain that is before the testimony, Aaron and his sons are to arrange it from evening to morning before the Lord. This is to be a lasting ordinance among the Israelites for generations to come.

Leviticus 17:7

17:7 So they must no longer offer their sacrifices to the goat demons, acting like prostitutes by going after them. This is to be a perpetual statute for them throughout their generations.