Numbers 3:38-39

38Moses and Aaron and his sons were to camp to the east of the tabernacle, toward the sunrise, in front of the tent of meeting. They were responsible for the care of the sanctuary on behalf of the Israelites. Anyone else who approached the sanctuary was to be put to death.

39The total number of Levites counted at the Lord’s command by Moses and Aaron according to their clans, including every male a month old or more, was 22,000.