Numbers 8:11

“And Aaron shall offer the Levites before the Lord, etc.] Or “wave” f85 them, as a wave offering, which was moved to and fro, backwards and forwards; not that they were actually so waved and moved to and fro by Aaron, which could not be done by him; though it is possible he might make such a motion himself, and they might do the like after him, thereby signifying that they belonged unto the Lord of the whole earth; and some think this testified their readiness to serve the Lord; to which may be added their constant employment in his service, being always in motion, doing one piece of service or another continually; as the people of God, and especially the ministers of the word, should be…”

“And Aaron shall offer the Levites--Hebrew, "as a wave offering"; and it has been thought probable that the high priest, in bringing the Levites one by one to the altar, directed them to make some simple movements of their persons, analogous to what was done at the presentation of the wave offerings before the Lord. Thus were they first devoted as an offering to God, and by Him surrendered to the priests to be employed in His service. The consecration ceremonial was repeated in the case of every Levite who was taken (as was done at a later period) to assist the priests in the tabernacle and temple. (See on Ch2 29:34).”

“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…”

“For an offering - Heb. for a wave - offering. Not that Aaron did so wave them, which he could not do, but that he caused them to imitate that motion, and to wave themselves toward the several parts of the world: whereby they might signify their readiness to serve God, according to their capacity wheresoever they should be. Numbers 8:12”

“8:11 The reference to Aaron’s raised hands suggests that Israel offered the Levites to the Lord as a “wave offering”—the type of offering lifted up to the Lord (cp. Lev 7:30). The Levites were dedicated to duties that made them “living and holy sacrifices” (cp. Rom 12:1).”

“offer: Heb. wave offering: Heb. wave-offering, Not that they were actually waved, but they were presented to God, as the God of heaven, and the Lord of the whole earth, as the wave offerings were; and in calling them wave-offerings, it was intimated to them that they must move to and fro with readiness in the business of their profession. Num 6:20; Exo 29:24; Lev 7:30, Lev 8:27, Lev 8:29 they may execute: Heb. they may be to execute, etc. Num 1:49-53, 3:5-43 Numbers 8:12”

“This transfer was to be completed by Aaron's waving the Levites as a wave-offering before Jehovah on behalf of the children of Israel, i.e., by his offering them symbolically to the Lord as a sacrifice presented on the part of the Israelites. The ceremony of waving consisted no doubt in his conducting the Levites solemnly up to the altar, and then back again. On the signification of the verb, see at Lev 7:30. The design of the waving is given in Num 8:11, viz., "that they might be to perform the service of Jehovah" ( Num 8:24-26 compared with Num 4:4-33). Numbers 8:12”