Leviticus 7:28

And the LORD spake unto Moses, saying,

The verse opens the Lord's instructions to Moses concerning the peace-offering, and in particular the priests' share in it. The peace offerings were especially an expression of thanksgiving to God, and they pointed forward to the death of Christ to preserve faith in the coming Redeemer in the hearts of the people, so strict obedience to them was of the greatest importance. In those instructions the fat alone was to be burned upon the altar as a type of the great Sacrifice. A certain specified portion was reserved for the priests, comprising the breast, the right shoulder, and certain smaller portions.

The rest, the greater part, was returned to the offerer to be eaten, directing all hearts in gratitude and faith to the great Sacrifice that takes away the sin of the world. That eating was to be by the offerer and his friends in a sacrificial feast. The instructions were exact so that priests could not claim more than their appointed share. This law was violated by the sons of Eli, who were not content with the allotted part but demanded an additional portion, refused to wait until the fat had been burned to God, claimed whatever portion pleased them and threatened to take it by violence, using the great number of sacrifices at the annual feasts to enrich themselves at the expense of the people.