Ambrose of Milan
Catena Aurea · Lukasevangelium 15
And he said, A certain man had two sons: And the younger of them said to his father, Father, give me the portion of goods that falleth to me. And he divided unto them his living. And not many days after the younger son gathered all together, and took his journey into a far country, and there wasted his substance with riotous living. And when he had spent all, there arose a mighty famine in that land; and he began to be in want. And he went and joined himself to a citizen of that country; and he sent him into his fields to feed swine. And he would fain have filled his belly with the husks that the swine did eat: and no man gave unto him. It follows, And he began to be in want. Fitly did he begin to be in want who abandoned the treasures of the wisdom and the knowledge of God, and the unfathomableness of the heavenly riches. It follows, And he went and joined himself to a citizen of that country.
For what is more afar off than to depart from one’s self, to be separate not by country but by habits. For he who severs himself from Christ is an exile from his country, and a citizen of this world. Fitly then does he waste his patrimony who departs from the Church.