John Chrysostom — as excerpted in the Catena Aurea on Luke 15:17-24

“(Hom. de Patre et duobus Filiis.) Or he bids them put shoes on his feet, either for the sake of covering the soles of his feet that he may walk firm along the slippery path of the world, or for the mortification of his members. For the course of our life is called in the Scriptures a foot, and a kind of mortification takes place in shoes; inasmuch as they are made of the skins of dead animals. He adds also, that the fatted calf must be killed for the celebration of the feast. For it follows, And bring the fatted calf, that is, the Lord Jesus Christ, whom he calls a calf, because of the sacrifice of a body without spot; but he called it fatted, because it is rich and costly, inasmuch as it is sufficient for the salvation of the whole world. But the Father did not Himself sacrifice the calf, but gave it to be sacrificed to others. For the Father permitting, the Son consenting thereto by men was crucified.”