Upon the burnt sacrifice - Upon the ashes of the continual burnt-offering Exodus 29:38, in accordance with Leviticus 6:12.

Aaron's sons shall burn it - As the fat was deemed the most valuable part of the animal, it was offered in preference to all other parts; and the heathens probably borrowed this custom from the Jews, for they burnt the omentum or caul in honor of their gods.

And Aaron's sons shall burn it on the altar,.... That is, the fat of the several parts before mentioned; this signified the sufferings of Christ, by which our peace is made, and by whose death we are reconciled to God: this rite of burning the fat of the inwards of sacrifices was used by the Pagans, and is still retained by the idolatrous Indians to this day (h):

upon the burnt sacrifice; which, as Gersom says, was the burnt offering of the daily sacrifice of the morning, which was offered first of all sacrifices; so Jarchi says,"we learn that the daily burnt offering preceded every other offering:''this was an eminent type of Christ's sacrifice:

which is upon the wood that is on the fire; that is, which burnt offering was laid upon the wood on the fire, and the fat of the peace offering upon that:

it is an offering made by fire, of a sweet savour unto the Lord; as Christ's sacrifice is, Ephesians 5:2; see Gill on Leviticus 1:9.

(h) See the Abridgment of Mr. Brainerd's Journal, published in 1748, p. 30.

This fat the priests were to burn upon the altar, over the burnt sacrifice, on the pieces of wood upon the fire. על־העלה does not mean "in the manner or style of the burnt-offering" (Knobel), but "upon (over) the burnt-offering." For apart from the fact that על cannot be shown to have this meaning, the peace-offering was preceded as a rule by the burnt-offering. At any rate it was always preceded by the daily burnt-offering, which burned, if not all day, at all events the whole of the forenoon, until it was quite consumed; so that the fat portions of the peace-offerings were to be laid upon the burnt-offering which was burning already. That this is the meaning of על־העלה is placed beyond all doubt, both by Leviticus 6:5, where the priest is directed to burn wood every morning upon the fire of the altar, and then to place the burnt-offering upon it (עליה), and upon that to cause the fat portions of the peace-offerings to evaporate in smoke, and also by Leviticus 9:14, where Aaron is said first of all to have burned the flesh and head of the burnt-offering upon the altar, then to have washed the entrails and legs of the animal, and burned them on the altar, העלה על, i.e., upon (over) the portions of the burnt-offering that were burning already.

And Aaron's sons shall burn it on the altar upon the burnt sacrifice, which is upon the wood that is on the fire: it is an offering made by fire, of a sweet savor unto the LORD.

3:5 Upon the burnt sacrifice - Either, Upon the remainders of it, which were yet burning; or rather, After it; for the daily burnt - offering was first to be offered, both as more eminently respecting God's honour; and as the most solemn and stated sacrifice, which should take place of all occasional oblations, and as a sacrifice of an higher nature, being for atonement, without which no peace could be obtained, nor peace offering offered with acceptance.

3:1-5 The peace-offerings had regard to God as the giver of all good things. These were divided between the altar, the priest, and the owner. They were called peace-offering, because in them God and his people did, as it were, feast together, in token of friendship. The peace-offerings were offered by way of supplication. If a man were in pursuit of any mercy, he would add a peace-offering to his prayer for it. Christ is our Peace, our Peace-offering; for through him alone it is that we can obtain an answer of peace to our prayers. Or, the peace-offering was offered by way of thanksgiving for some mercy received. We must offer to God the sacrifice of praise continually, by Christ our Peace; and then this shall please the Lord better than an ox or bullock.