Leviticus 1:5

5.And he shall kill the bullock. The ceremony of killing is subjoined, viz., that the priest should prepare the victim itself, and pour its blood upon the altar, for it was not allowable for a private person to kill the victim with his own hands, but what the priest did in their name was transferred to them. (250) But this is worth remarking, that although they brought the pledge of reconciliation from their home, yet that the ministers of expiation were to be sought elsewhere, since no one was competent for so illustrious an office, save he who was graced by the holy unction of God. It was, therefore, plainly manifested that all mortals are unworthy of coming near God to propitiate Him, and that the hands of all are in a manner polluted or profane except those which God himself has purged. For the honor of sacrificing came from nowhere else but from the grace of the Spirit, of which the external anointing was a pledge. We now understand how it was that individuals offered sacrifices to God, and yet that the priest alone performed this office. The altar was sprinkled with the blood, that the people might know that the blood poured from the victim did not fall on the ground, but was consecrated to God, and breathed, as it were, a sweet savor; just as now the blood of Christ appears before His face. I pass by the rest, since it does not seem worth while to enlarge on the third kind of offering, i.e., of the birds. Yet we must recollect that thus far Moses only speaks of the burnt-offerings, whose flesh was burned; for this was not the case with all, as we shall see hereafter. Although, then, it is twice said that “the priests shall lay the parts, the head and the fat,” etc., we must not understand it as if he only commanded the fat and the head to be burned, but that nothing was to be left the skin. Some think that פדר pheder, (251) is a dissevered head, nor do I reject their opinion, provided we do not exclude the fat. Whatever was filthy in the victim, God would have to be washed, that it might not contaminate it. The question now arises why it was burned either wholly or partially. My own opinion is, that by the fire the efficacy of the Spirit is represented, on which all the profit of the sacrifices depends; for unless Christ had suffered in the Spirit, He would not have been a propitiatory sacrifice. Fire, then, was as the condiment which gave their true savor to the sacrifices, because the blood of Christ was to be consecrated by the Spirit, that it might cleanse us from all the stains of our sins. This God would have more fully represented in the burnt-offerings, yet no victim was offered of which some part was not consumed by fire.