Numbers 3:41-45

41Set the Levites apart for me in place of all the firstborn of Bnei-Yisrael, and, all the livestock of the Levites in place of the firstborn of the livestock of Bnei-Yisrael. I am Adonai.”

42So Moses counted all the firstborn of Bnei-Yisrael as Adonai commanded him.

43The sum total of the firstborn males of Bnei-Yisrael, one month old and upward, listed by name, was 22,273.

44Again Adonai spoke to Moses saying,

45“Take the Levites in place of all the firstborn of Bnei-Yisrael, and the livestock of the Levites in place of their livestock. The Levites will be Mine. I am Adonai.