Leviticus 10:8-11

8Then the LORD said to Aaron, 9“You and your sons are not to drink wine or strong drink when you enter the Tent of Meeting, or else you will die; this is a permanent statute for the generations to come. 10You must distinguish between the holy and the common, between the clean and the unclean, 11so that you may teach the Israelites all the statutes that the LORD has given them through Moses.”