Exodus 24:5

“And he sent young men of the children Israel, etc.] To the altar under the hill he had these young men, according to Jarchi, were the firstborn of the children of Israel; and so the Targums Onkelos and Jonathan; and the latter adds, “for unto this hour the worship was among the firstborn, as yet the tabernacle of the covenant was not made, and as yet the priesthood was not given to Aaron.” But though this is a notion that has obtained among learned men, both Jews and Christians, it has been called in question by some, who have such reasons against it, as are not easily refuted. And very probably, as the seventy elders were such as were selected from the senior and graver part of the people,…”

“young men--priests (Exo 19:22), probably the oldest sons of particular families, who acted under the direction of Moses. oxen--Other animals, though not mentioned, were offered in sacrifice (Heb 9:18-20).”

“Young men of the children of Israel - See Exodus 19:22; Exodus 28:1; Leviticus 1:5. Burnt offerings ... peace offerings - The burnt offerings Leviticus 1:0 figured the dedication of the nation to Yahweh, and the peace offerings Leviticus 3:0 their communion with Yahweh and with each other. return to 'Top of Page'”

“young men: Exo 19:22 burnt offerings: Exo 18:12; Lev. 1:1-17 peace offerings: Lev. 3:1-17, Lev 7:11-21 Exodus 24:6”

“After the foundation and soil had been thus prepared in the place of sacrifice, for the fellowship which Jehovah was about to establish with His people; Moses sent young men of the children of Israel to prepare the sacrifices, and directed them to offer burnt-offering and sacrifice slain-offerings, viz., שׁלמים, "peace-offerings (see at Lev 3:1) for Jehovah," for which purpose פּרים, bullocks, or young oxen, were used. The young men were not first-born sons, who had officiated as priests previous to the institution of the Levitical priesthood, according to the natural right of primogeniture, as Onkelos supposes; nor were they the sons of Aaron, as Augustine maintains: they simply acted as…”