Numbers 3:9 And thou shalt give the Levites unto Aaron and to his sons: they are wholly given unto him out of the children of Israel.
God made Aaron and his family the priests. He gave the Levites to Aaron to help him accomplish the work that he was to do. They would move the Tabernacle. They would set it up and take it down. They would help with the sacrifices.
That is much what God did in the New Testament when He gave the church those first deacons. They were there to help the pastors, teachers, elders give themselves totally to the Word of God and prayer. They would protect the pastor and allow him to do the work that God had called him to do.
God has been great to the church to provide for every area of service!