Humble servant

The apostles said to the Lord, "Increase our faith!"
And the Lord said, "If you had faith like a grain of mustard seed, you could say to this mulberry tree, 'Be uprooted and planted in the sea,' and it would obey you. 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.'"

Luke 17:5-10

Jesus gives the work of a servant as an answer to the apostles' lack of faith. He does not say "hear and know" he says "hear and obey." The work that God gives us is good and does accomplish his purpose for it. If we have done the duty God has given us, we don't look for another reward, say of praise or position, but the work itself is the reward. It is a gift that comes down from the Father of lights to grow our faith.
So the very duty that God gives us is himself and he is forming us into the image of his son. Just as Christ "learned obedience through what he suffered," so we also are made perfect through our duty as servants and our suffering with him. Our work is not meritorious, but forming. We do not work for some thing to be held in the hand or received as a thing apart from very God. There is no salvation outside Christ, not a gift given other than his own being. When he gives us the gift of faith, he gives himself. When he gives us grace, he gives himself. When he gives us work, he gives himself and we grow into him who is our head. If his very life is our faith and our work, we should rightly say, "we are unworthy servants; we have only done what was our duty."