'Serving' in the Bible

These are those numbered of the families of the Kohathite, every one who is serving in the tent of meeting, whom Moses and Aaron numbered, by the command of Jehovah, by the hand of Moses.

These are those numbered of the families of the sons of Gershon, every one who is serving in the tent of meeting, whom Moses and Aaron numbered by the command of Jehovah.

and to the sons of Levi, lo, I have given all the tenth in Israel for inheritance in exchange for their service which they are serving -- the service of the tent of meeting.