Reference

Numbers 3:14

And the Lord spake unto Moses in the wilderness of Sinai, saying,
12

And I, behold, I have taken the Levites from among the children of Israel instead of all the firstborn that openeth the matrix among the children of Israel: therefore the Levites shall be mine;

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 spake unto Moses in the wilderness of Sinai, saying,

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Number the children of Levi after the house of their fathers, by their families: every male from a month old and upward shalt thou number them.

16

And Moses numbered them according to the word of the Lord, as he was commanded.