Num Numbers, chapter Book of Numbers, chapter 3
And the Lord spoke to Moses, saying: I have taken the Levites from the children of Israel, for every firstborn that openeth the womb among the children of Israel, and the Levites shall be mine. Exo 29:24; Num 8:16For every firstborn is mine: since I struck the firstborn in the land of Egypt: I have sanctified to myself whatsoever is firstborn in Israel both of man and beast, 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