Gregory the Great
Patristic
c. A.D. 540–604
“Hence under the divine law the priest receives the shoulder for sacrifice, and this the right one and separate; to signify that his action should be not only profitable, but even singular; and that he should not merely do what is right among bad men, but transcend even the well-doers among those that are under him in the virtue of his conduct, as he surpasses them in the dignity of his order.”