Numbers 3:9-19

9 Assign the L'vi'im to Aharon and his sons; their one responsibility in regard to the people of Isra'el is to serve him.
10 You are to appoint Aharon and his sons to carry out the duties of cohanim; anyone else who involves himself is to be put to death."
11 ADONAI said to Moshe,
12 "I have taken the L'vi'im from among the people of Isra'el in lieu of every firstborn male that is first from the womb among the people of Isra'el; the L'vi'im are to be mine.
13 All the firstborn males belong to me, because on the day that I killed all the firstborn males in the land of Egypt, I separated for myself all the firstborn males in Isra'el, both human and animal. They are mine; I am ADONAI."
14 ADONAI said to Moshe in the Sinai Desert,
15 "Take a census of the tribe of Levi by clans and families. Count every male a month old or over."
16 Moshe counted them in the manner ADONAI had said, as he had been ordered.
17 The names of the sons of Levi were Gershon, K'hat and M'rari.
18 The names of the sons of Gershon were Livni and Shim'i; they fathered their respective clans;
19 likewise the sons of K'hat -'Amram,Yitz'har, Hevron and 'Uzi'el -
Complete Jewish Bible Copyright 1998 by David H. Stern. Published by Jewish New Testament Publications, Inc. All rights reserved. Used by permission.