Num Numbers, chapter Book of Numbers, chapter 3
The Lord told Moses, “I've taken the Levites from the Israelites in place of every one of their firstborn. The Levites belong to me Exo 29:24; Num 8:16because all the firstborn are mine. When I killed every firstborn in Egypt I set apart as holy to me all the firstborn of Israel, human and animal. They are mine. I am the Lord.”Exo 13:2; Exo 22:29; Exo 34:19; Lev 27:26; Num 8:17; Luk 2:23