Augustine of Hippo
Catena Aurea · Lukasevangelium 17
But which of you, having a servant plowing or feeding cattle, will say unto him by and by, when he is come from the field, Go and sit down to meat? And will not rather say unto him, Make ready wherewith I may sup, and gird thyself, and serve me, till I have eaten and drunken; and afterward thou shalt eat and drink? Doth he thank that servant because he did the things that were commanded him? I trow not. So likewise ye, when ye shall have done all those things which are commanded you, say, We are unprofitable servants: we have done that which was our duty to do.
(de Quæst. Ev. l. 2. qu. 39.) Or else; To the many who understand not this faith in the truth already present, our Lord might seem not to have answered the petitions of His disciples. And there appears a difficulty in the connexion here, unless we suppose He meant the change from faith to faith, from that faith, namely, by which we serve God, to that whereby we enjoy Him. For then will our faith be increased when we first believe the word preached, next the reality present. But that joyful contemplation possesseth perfect peace, which is given unto us in the everlasting kingdom of God. And that perfect peace is the reward of those righteous labours, which are performed in the administration of the Church. Be then the servant in the field ploughing, or feeding, that is, in this life either following his worldly business, or serving foolish men, as it were cattle, he must after his labours return home, that is, be united to the Church.