The Levites: Services of Ministering to Priests
Source: TTT
Numbers 3:6, 7
“Bring the tribe of Levi and present them to Aaron the priest to assist him. / They are to perform duties for him and for the whole congregation before the Tent of Meeting, attending to the service of the tabernacle.
Numbers 18:2
But bring with you also your brothers from the tribe of Levi, the tribe of your father, that they may join you and assist you and your sons before the Tent of the Testimony.