Numbers 8:16–18

16 For they are uwholly given to me from among the people of Israel. vInstead of all who open the womb, the firstborn of all the people of Israel, I have taken them for myself. 17 wFor all the firstborn among the people of Israel are mine, both of man and of beast. On the day that I struck down all the firstborn in the land of Egypt I consecrated them for myself, 18 and I have taken the Levites instead of all the firstborn among the people of Israel.