Numbers 3:5-8

And the LORD spoke to Moses, saying: “Bring the tribe of Levi near, and present them before Aaron the priest, that they may serve him. And they shall attend to his needs and the needs of the whole congregation before the tabernacle of meeting, to do the work of the tabernacle. Also they shall attend to all the furnishings of the tabernacle of meeting, and to the needs of the children of Israel, to do the work of the tabernacle.