Charles Ellicott Commentary Leviticus 9:4

"and an ox and a ram for peace-offerings, to sacrifice before Jehovah; and a meal-offering mingled with oil: for to-day Jehovah appeareth unto you." — Leviticus 9:4 (ASV)

Also a bullock and a ram. —The elders were thus to bring on behalf of the people:

1. a he-goat for a sin offering;
2. a yearling calf and a yearling sheep for a burnt offering; and
3. an ox and a ram for a peace offering.

A meat offering mingled with oil. —The oil was to be added because, with the exception of the small portion offered to the Lord, the meat offering was the privilege of the officiating priests who consumed it along with their share of the sacrificial animals, and thus the cakes had to be made palatable for the priestly meal. .

For to-day the Lord will appear unto you. —That is, prepare and sanctify yourselves with these sacrifices, because the Lord will manifest himself in a special way to signify his approval of the inauguration of Aaron and his family to the priesthood.