scrupulous and conscientious fulfilment of duty in connection with their office, but extended to all the sin which attached to the official acts of the priests, on account of the sinfulness of their nature. It was to wipe out these sins and defilements, that the annual expiation of the holy things on the day of atonement had been appointed (Lev 16:16.). The father's house of Aaron, i.e., the Levitical family of Kohath, was also to join in bearing the iniquity of the sanctuary, because the oversight of the holy vessels of the sanctuary devolved upon it (Num 4:4).
verses 2-4
Aaron was also to bring his (other) brethren (sc., to the sanctuary), viz., the tribe of Levi, that is to say, the Gershonites and Merarites, that they might attach themselves to him and serve him, both him (ואתּה) and his sons, before the tent of testimony, and discharge the duties that were binding upon them, according to Num 4:24., Num 4:31. (cf. Num 3:6-7; Num 8:26). Only they were not to come near to the holy vessels and the altar, for that would bring death both upon them and the priests (see at Num 4:15). On Num 18:4, cf. Num 1:53 and Num 3:7.
verses 5-7
The charge of the sanctuary (i.e., the dwelling) and the altar (of burnt-offering) devolved upon Aaron and his sons, that the wrath of God might not come again upon the children of Israel (see Num 8:19), - namely, through such illegal acts as Nadab and Abihu (Lev 10:2), and the company of Korah (Num 16:35), had committed. To this end God had handed over the Levites to them as a gift, to be their assistants (see at Num 3:9 and Num 8:16, Num 8:19). But Aaron and his sons were to attend to the priesthood “with regard to everything of the altar and within the vail” (i.e., of the most holy place, see Lev 16:12). The allusion is to all the priestly duties from the altar of burnt-offering to the most holy place, including the holy place which lay between. This office, which brought them into the closest fellowship with the Lord, was a favour accorded to them by the grace of God. This is expressed in the words, “as a service of gift (a service with which I present you) I give you the priesthood.” The last words in Num 18:7 are the same as in Num 1:51; and “stranger” (zar), as in Lev 22:10.
verses 8-18
The Revenues of the Priests. - These are summed up in Num 18:8 in these words, “I give thee the keeping of My heave-offerings in all holy gifts for a portion, as an eternal statute.” The notion of משׁמרת, keeping, as in Exo 12:6; Exo 16:23, Exo 16:32, is defined in the second parallel clause as משׁחה, a portion (see at Lev 7:35).
