John Gill Commentary Leviticus 7:5

"and the priest shall burn them upon the altar for an offering made by fire unto Jehovah: it is a trespass-offering." — Leviticus 7:5 (ASV)

And the priest shall burn them upon the altar
Fat taken off of the several parts before mentioned, and the kidneys: which were to be

[for] an offering made by fire unto the Lord ;
and was acceptable to him, being typical of the offering of Christ, which is a sweet smelling savour, bearing the fire of divine wrath in the room and stead of his people:

it [is] the trespass [offering] ;
an offering for a trespass committed, to make atonement for it; and this part of it, the burning of the fat, was properly the offering to the Lord, all the rest were the priest's, as follows.