Gregory the Great — as excerpted in the Catena Aurea on John 6:22-27

“(xxiii. Moral. [c. xxv.]) In their persons too our Lord condemns all those within the holy Church, who, when brought near to God by sacred Orders, do not seek the recompense of righteousness, but the interests of this present life. To follow our Lord, when filled with bread, is to use Holy Church as a means of livelihood; and to seek our Lord not for the miracle’s sake, but for the loaves, is to aspire to a religious office, not with a view to increase of grace, but to add to our worldly means.”