Charles Ellicott Commentary Exodus 24:5

"And he sent young men of the children of Israel, who offered burnt-offerings, and sacrificed peace-offerings of oxen unto Jehovah." — Exodus 24:5 (ASV)

Young men ... who offered burnt offerings.—It should be noted that, even after the appointment of the Levitical priesthood, the acts of slaughtering the victims and arranging the flesh upon the altar were regarded as appropriately performed by any Israelite (Leviticus 1:5–6; Leviticus 1:11–12, and other similar passages). The sprinkling of the blood and the lighting of the fire were the special sacrificial acts reserved for the priest (Leviticus 1:5; Leviticus 1:7; Leviticus 1:11; Leviticus 1:13). At this time, before the Levitical priesthood had been instituted, the sprinkling of the blood seems to have been the sole act reserved. Young men were employed to slay the animals as they were best qualified by their strength to deal with them.

Burnt offerings ... peace offerings.—Burnt offerings were both expiatory and signs of self-dedication. Peace offerings were indications of humanity’s gratitude for mercies received. Both were now offered together, to mark:

1. Israel’s thankfulness for being taken into covenant.
2. Israel’s determination to consecrate itself wholly to the service of God.