Numbers 18:2

that they may be joined This is a play on words, similar to that in Genesis 29:34, the verb lâwâh(לוה) being employed to explain the word Lçwî-Levite," so that the latter is understood to denote -one who is joinedto the priests as a servant." Whether this was the originalmeaning and derivation is doubtful.

shall be before the tent shall preside over the tent. The preposition is not local, but comprises sacred duties both within the tent and outside in the court.