Thematic Bible: Supererogation

Son of man, tell the Israelites that when someone good sins, the good he has done will not save him. If an evil person stops doing evil he will not be punished, and if a good man starts sinning, his life will not be spared. I may promise life to someone good, but if he starts thinking that his past goodness is enough and begins to sin, I will not remember any of the good he did. He will die because of his sins.

The same applies to you. When you have done all you have been told to do, you say, we are unworthy servants. We have done what we ought to have done. Verse ConceptsCommands, in NTServants, GoodDuty