Luke 17:7-10

But which of you having a servant ploughing, or feeding cattle, will say to him, when he is come from the field: Immediately go, sit down to meat: And will not rather say to him: Make ready my supper, and gird thyself, and serve me, whilst I eat and drink, and afterwards thou shalt eat and drink? Doth he thank that servant, for doing the things which he commanded him? I think not. So you also, when you shall have done all these things that are commanded you, say: We are unprofitable servants; we have done that which we ought to do.

Commentary

This parable stresses the importance of remembering that we can't work our way into Heaven, that God doesn't need our offerings, and that God owes us nothing. Our sharing in His Kingdom is solely by His grace, and we are to be grateful for whatever He gives us --- which will always be in accordance with His love and mercy.

The Douay-Rheims footnote explains why the word "unprofitable" is used here: "Because our service is of no profit to our master; and he justly claims it as our bounden duty. But though we are unprofitable to him, our serving him is not unprofitable to us; for he is pleased to give by his grace a value to our good works, which, in consequence of his promise, entitles them to an eternal reward."