Numbers 3:11-13

Young's Literal Translation

¹¹ And Jehovah speaketh unto Moses, saying,

¹² `And I, lo, I have taken the Levites from the midst of the sons of Israel instead of every first-born opening a womb among the sons of Israel, and the Levites have been Mine;

¹³ for Mine [is] every first-born, in the day of My smiting every first-born in the land of Egypt I have sanctified to Myself every first-born in Israel, from man unto beast; Mine they are; I [am] Jehovah.'