Deuteronomy 18:3
And this shall be the priest’s due from the people, from them that offer a sacrifice, whether it be ox or sheep; and they shall give unto the priest the shoulder, and the two cheeks, and the maw. And this shall be the priest’s due from the people, from them that offer a sacrifice, whether it be ox or sheep; and they shall give unto the priest the shoulder, and the two cheeks, and the maw.
The priest's due from the people, from those offering a sacrifice of ox or sheep, was the shoulder and the two cheeks and the maw, that is the stomach. The meat came to the priests from only a limited class of offerings, for the fat was reserved to be burned to the Lord and only the remaining lean portion went to the priests. The required share belongs among the priestly demands of the Mosaic ritual that could add to the burden of the people, though portrayals that magnify that burden by it go beyond the mark.
In the peace-offering type the two cheeks assigned to the priest foreshadow Christ being spat upon in the face. They foreshadow the suffering of the Prince of Peace in giving His cheeks to those who plucked out the hair. They also signify the reproach and shame that God's children may be called to bear.