Leviticus 10:8-10

8Then the Lord spoke to Aaron, saying,

9“Do not drink wine or intoxicating drink, neither you nor your sons with you, when you come into the Tent of Meeting, so that you will not die—it is a permanent statute throughout your generations—

10and to make a distinction and recognize a difference between the holy (sacred) and the common (profane), and between the [ceremonially] unclean and the clean;