Luke 17:5-10

And the Apostles said to the Lord, "Increase our faith." But the Lord said: "If you have faith like a grain of mustard seed, you may say to this mulberry tree, 'Be uprooted, and be transplanted into the sea.' And it would obey you. But which of you, having a servant plowing or feeding cattle, would say to him, as he was returning from the field, 'Come in immediately; sit down to eat,' and would not say to him: 'Prepare my dinner; gird yourself and minister to me, while I eat and drink; and after these things, you shall eat and drink?' Would he be grateful to that servant, for doing what he commanded him to do? I think not. So too, when you have done all these things that have been taught to you, you should say: 'We are useless servants. We have done what we should have done.' "