Charles Spurgeon Commentary Leviticus 16:22-25

"and the goat shall bear upon him all their iniquities unto a solitary land: and he shall let go the goat in the wilderness. And Aaron shall come into the tent of meeting, and shall put off the linen garments, which he put on when he went into the holy place, and shall leave them there: and he shall bathe his flesh in water in a holy place, and put on his garments, and come forth, and offer his burnt-offering and the burnt-offering of the people, and make atonement for himself and for the people. And the fat of the sin-offering shall he burn upon the altar." — Leviticus 16:22-25 (ASV)

Only the fat of it, the best of it, was burned on the altar, for sin offerings were not acceptable to God. They were regarded as being filled with impurity because of the sin which they brought to mind; for this reason the bullock and the goat of the sin offering had to be burned outside the camp: Wherefore Jesus also, that he might sanctify the people with his own blood, suffered without the gate, as our sin offering. Yet, since the fat was accepted on the altar, so is Christ, even as our sin offering, acceptable before God.