Luke 17:7-10 Unworthy Servants.  “Will any one of you who has a servant plowing or keeping sheep say to him when he has come in from the field, ‘Come at once and recline at table’?  Will he not rather say to him, ‘Prepare supper for me, and dress properly, and serve me while I eat and drink, and afterward you will eat and drink’?  Does he thank the servant because he did what was commanded?  So you also, when you have done all that you were commanded, say, ‘We are unworthy servants; we have only done what was our duty.’”
Is Jesus saying that Christians are unworthy servants ? Yes. Jesus didn’t go to the cross for us because of how good we are, but because of his mercy towards us. We are sinners who needed a savior.
But in these verses he is saying to the disciples that they (and we) must be careful not to become proud of the things we do for Him. This is what we ought to be doing.
We have been saved to do good works by following and obeying Jesus. This is the expected result of our salvation.
Ephesians 2:8-10 8] For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,  not a result of works, so that no one may boast.  For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.