Numbers 3:14-16

Young's Literal Translation

¹⁴ And Jehovah speaketh unto Moses in the wilderness of Sinai, saying,

¹⁵ `Number the sons of Levi by the house of their fathers, by their families; every male from a son of a month and upward thou dost number them.'

¹⁶ And Moses numbereth them according to the command of Jehovah, as he hath been commanded.