Numbers 8:19

“And I have given the Levites [as] a gift to Aaron and his sons, from among the children of Israel, etc.] Or I have given the Levites that were given; that is, the Lord gave to Aaron and his sons the Levites, that were first given to him; as they were, when brought before him, and the children of Israel laid hands on them, and they were offered before the Lord, (<040810>Numbers 8:10,11); to do the service of the children of Israel in the tabernacle of the congregation; to do what otherwise they must have done, watch and guard the tabernacle, carry the sacrifices to the priests, assist them at the altar, take down and set up the tabernacle, and carry it, and the vessels of it, from place to…”

“to make an atonement for the children of Israel, &c.--to aid the priests in that expiatory work; or, as the words may be rendered, "to make redemption for" the Levites being exchanged or substituted for the first-born for this important end, that there might be a sanctified body of men appointed to guard the sanctuary, and the people not allowed to approach or presumptuously meddle with holy things, which would expose them to the angry judgments of Heaven.”

“The Levites could only undertake their duties Numbers 3:0; Numbers 4:0 after the formal exchange of the Levites for the first-born Numbers 3:44-51. The distinction between the “consecration” of the priests Leviticus 8:0 and the less solemn “purification” Numbers 8:21 of the Levites is marked. These rites of purification are similar to those incumbent on the priests of Egypt. Numbers 8:7 Water of purifying - literally, “sin water:” i. e. water to cleanse from sin; no doubt taken from the laver of the sanctuary, which was used by the priests for purification before they went into the tabernacle to minister (compare Numbers 5:17; Exodus 30:18 ff). The “sprinkling” of so large a body of men…”

“To do the service of Israel - To serve God in their stead, to do what otherwise they had been obliged to do in their own persons. To make an atonement - Not by offering sacrifices, which the priests alone might do, but by assisting the priests in that expiatory work, and by a diligent performance of all the parts of their office, whereby God was pleased both with them and with the people. That there be no plague - This is added as a reason why God appointed them to serve in the tabernacle, that they might guard it, and not suffer any of the people to come near it, or meddle with holy things, which if they did, it would certainly bring a plague upon them. Numbers 8:26”

“8:19 A plague was an appropriate punishment for unlawful actions (11:33; 14:37).”

“I have given: Num 3:6-9, Num 18:2-6; Ch1 23:28-32; Eze 44:11-14 a gift: Heb. given that there: Num 1:53, Num 16:46, Num 18:5; Sa1 6:19; Ch2 26:16-20 Numbers 8:21”