Numbers 18:1-5

The LORD said to Aaron, “You, your sons, and your family are now responsible for any wrongs done against the Holy Place; you and your sons are responsible for any wrongs done against the priests. Bring with you your fellow Levites from your tribe, and they will help you and your sons serve in the Tent of the Agreement. They are under your control, to do all the work that needs to be done in the Tent. But they must not go near the things in the Holy Place or near the altar. If they do, both you and they will die. They will join you in taking care of the Meeting Tent. They must do the work at the Tent, and no one else may come near you. “You must take care of the Holy Place and the altar so that I won’t become angry with the Israelites again.