Thematic Bible: Supererogation

You, son of man, tell the children of your people, The righteousness of the righteous shall not deliver him in the day of his disobedience; and as for the wickedness of the wicked, he shall not fall thereby in the day that he turns from his wickedness; neither shall he who is righteous be able to live thereby in the day that he sins. When I tell the righteous, that he shall surely live; if he trust to his righteousness, and commit iniquity, none of his righteous deeds shall be remembered; but in his iniquity that he has committed, therein shall he die.

Even so you also, when you have done all the things that are commanded you, say, 'We are unworthy servants. We have done our duty.'" Verse ConceptsCommands, in NTServants, GoodDuty