Numbers 8:17

“For all the firstborn of the children of Israel [are] mine, [both] men and beasts, etc.] Not only in common with other of his creatures, but in a special respect on account of his signal deliverance of them; they were his, as Jarchi expresses it, by the line of judgment, or rule of justice and equity, because he protected them among the firstborn of the Egyptians, saved them when he slew theirs, as follows: in the day that I smote every firstborn in the land of Egypt; both of men and beasts: I sanctified them for myself; claimed them as his own, and set them apart for his own use, or ordered them to be set apart: (see <021302>Exodus 13:2).”

“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…”

“all the: Num 3:13; Exo 13:2, Exo 13:12-15; Luk 2:23 on the day: Exo 12:29; Psa 78:51, Psa 105:36, Psa 135:8; Heb 11:28 I sanctified: Exo 13:14, Exo 13:15, Exo 29:44; Lev 27:14, Lev 27:15, Lev 27:26; Eze 20:12; Joh 10:36, Joh 17:19; Heb 10:29; Jam 1:18 Numbers 8:19”