Numbers 18:2-4

Webster_Strongs(i)
  2 H251 And thy brethren H4294 also of the tribe H3878 of Levi H7626 , the tribe H1 of thy father H7126 [H8685] , bring H3867 [H8735] thou with thee, that they may be joined H8334 [H8762] to thee, and minister H1121 to thee: but thou and thy sons H6440 with thee shall minister before H168 the tabernacle H5715 of witness.
  3 H8104 [H8804] And they shall keep H4931 thy charge H4931 , and the charge H168 of all the tabernacle H7126 [H8799] : only they shall not come near H3627 the vessels H6944 of the sanctuary H4196 and the altar H4191 [H8799] , that neither they, nor ye also, die.
  4 H3867 [H8738] And they shall be joined H8104 [H8804] to thee, and keep H4931 the charge H168 of the tabernacle H4150 of the congregation H5656 , for all the service H168 of the tabernacle H2114 [H8801] : and a stranger H7126 [H8799] shall not come near to you.