A Servant's Duty

Luke 17:7-10 (GNT)  "Suppose one of you has a servant who is plowing or looking after the sheep.  When he comes in from the field, do you tell him to hurry along and eat his meal?  Of course not! Instead, you say to him, 'Get my supper ready, then put on your apron and wait on me while I eat and drink; after that you may have your meal.'  The servant does not deserve thanks for obeying orders, does he?  It is the same with you; when you have done all you have been told to do, say, 'We are ordinary servants; we have only done our duty.' "