Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
Numbers Chapter 18
The iniquity of the sanctuary - i. e. the guilt of the offences which an erring people would be continually committing against the majesty of God, when brought into contact, through the ordinances, with the manifestations of His presence. Compare the marginal reference.
The iniquity of your priesthood - As the priests themselves were but men, they were strengthened to bear the iniquity of their own unintentional offences, by being entrusted with the ceremonial means of taking it away (compare Lev. 16). The word "bear" has, in the Old Testament, this double sense of "enduring" and "removing;" but in the person of Christ, who atoned by His own endurance, the two axe in effect one.
A stranger - i. e. every one not a Levite. So in Num 18:7, it denotes each one who was not a priest: compare Num 3:10; Num 16:40.
The Lord instructs here the priests that the office which they fill, and the help which they enjoy, are gifts from Him, and are to be viewed as such.
By reason of the anointing - See Lev 7:35.
In the most holy place - Rather, "among the most holy things;" as in Num 4:4 : i. e. "As the most holy of things shalt thou eat it." Accordingly, only the males of the priestly families could eat of the things here specified.
Surely redeem ... redeem - A stronger expression is intentionally used in reference to the redemption of the first-born of man than in reference to that of unclean beasts. For the rule as to the former admitted of no exception: the owner of the latter, if unwilling to redeem, might destroy the beasts. Compare the marginal references.
A covenant of salt - Compare the marginal reference. covenants were ordinarily cemented in the East by the rites of hospitality; of which salt was the obvious token, entering as it does into every article of diet. It indicates perpetuity: compare Lev 2:13 note.
I am thy part and thine inheritance - Compare the marginal references.
Abraham paid tithes to Melchizedek: Jacob had promised the tithe of all wherewith God blessed him if he should return in peace to his father's house. But now first the Lord's tithes are assigned to the Levites for their support (compare Lev 27:30). The payment of tithes to them is recognized in Neh 10:37; Neh 12:44; Tobit 1:7.
Bear their iniquity - The words probably refer to the iniquity of the people; who would, had they approached the tabernacle have fallen, from their proneness to transgress, into overt acts of offence. Against such a result they were, through the ministrations of the Levites, mercifully protected. Compare Num 18:1.
Here the tithes (and in Num 18:26 the priestly tithes) are to be dedicated to their purpose by the ceremony of heaving them to the Lord. The tithes, being solemnly set apart for sacred purposes, became virtually a heave-offering, like the gifts for the tabernacle Exo 25:2.
Reckoned unto you - Or, by you. The Levites were, of their tithes, to pay tithe to the priests, just as other Israelites paid tithe to the Levites.
Out of all your gifts - The spirit of this law would extend to all the revenues of the Levites; of the increase of their cattle, as well as of their tithes, a tithe would be paid by them for the Lord's service.
Neither shall ye pollute ... - Rather, and by not polluting the holy things of the children of Israel, ye shall not die.