Numbers 3:2

3:2 These are the names of the sons of Aaron: Nadab, the firstborn, and Abihu, Eleazar, and Ithamar.

Numbers 3:8

3:8 And they are responsible for all the furnishings of the tent of meeting, and for the needs of the Israelites, as they serve ¹  in the tabernacle.

¹ tn The construction uses the infinitive construct (epexegetically) followed by its cognate accusative. It would convey “to serve the service of the tabernacle,” but more simply it may be rendered as “serving.” Their spiritual and practical service is to serve.