Numbers 3:13-15

21st Century King James Version

¹³ because all the firstborn are Mine; for on the day that I smote all the firstborn in the land of Egypt I hallowed unto Me all the firstborn in Israel, both man and beast. Mine shall they be: I am the Lord.”

¹⁴ And the Lord spoke unto Moses in the Wilderness of Sinai, saying:

¹⁵ “Number the children of Levi according to the house of their fathers, by their families. Every male from a month old and upward shalt thou number them.”