Numbers 1:48-50

Young's Literal Translation

⁴⁸ seeing Jehovah speaketh unto Moses, saying,

⁴⁹ `Only, the tribe of Levi thou dost not number, and their sum thou dost not take up in the midst of the sons of Israel;

⁵⁰ and thou, appoint the Levites over the tabernacle of the testimony, and over all its vessels, and over all that it hath; they bear the tabernacle, and all its vessels, and they serve it; and round about the tabernacle they encamp.