Numbers 3:38-40

New Revised Standard Version Catholic Edition

³⁸ Those who were to camp in front of the tabernacle on the east—in front of the tent of meeting toward the east—were Moses and Aaron and Aaron’s sons, having charge of the rites within the sanctuary, whatever had to be done for the Israelites; and any outsider who came near was to be put to death. ³⁹ The total enrollment of the Levites whom Moses and Aaron enrolled at the commandment of the Lord, by their clans, all the males from a month old and upward, was twenty-two thousand.

The Redemption of the Firstborn

⁴⁰ Then the Lord said to Moses: Enroll all the firstborn males of the Israelites, from a month old and upward, and count their names.