Gregory the Great
Catena Aurea · Johannesevangelium 10
I am the good shepherd: the good shepherd giveth his life for the sheep. But he that is an hireling, and not the shepherd, whose own the sheep are not, seeth the wolf coming, and leaveth the sheep, and fleeth: and the wolf catcheth them, and scattereth the sheep. The hireling fleeth, because he is an hireling, and careth not for the sheep.
(Hom. in Evang. xiv.) Some there are who love earthly possessions more than the sheep, and do not deserve the name of a shepherd. He who feeds the Lord’s flock for the sake of temporal hire, and not for love, is an hireling, not a shepherd. An hireling is he who holds the place of shepherd, but seeketh not the gain of souls, who panteth after the good things of earth, and rejoices in the pride of station.