Numbers 8:17-19

New International Version

¹⁷ Every firstborn male in Israel, whether human or animal,^(A) is mine. When I struck down all the firstborn in Egypt, I set them apart for myself.^{(B) 18} And I have taken the Levites in place of all the firstborn sons in Israel.^{(C) 19} From among all the Israelites, I have given the Levites as gifts to Aaron and his sons^(D) to do the work at the tent of meeting on behalf of the Israelites^(E) and to make atonement for them^(F) so that no plague will strike the Israelites when they go near the sanctuary.”