Unnamed Elder from Pherme: Do not suppose you have done good

 It is prideful for you to suppose that when you were in the world you did good and lived well; for this is how the Pharisee thought (when he was boasting in the Temple) and he lost all the good that he had accomplished.(cf. Luke 18:11-12,14) Now if, on the other hand, you think that you are not doing anything good, this is sufficient for you to be saved; for this is humility. It was in the way (through humility and self-deprecation) that the Publican, who had done nothing good, was justified. (cf. Luke 18:13-14). A sinful and negligent man who feels contrition of heart and humility is more pleasing before God that one who does many good deeds, but is of the opinion that he has completely succeeded in accomplishing something good.

+Unnamed Elder¹ from Pherme, from Themes in Orthodox Patristic Psychology, book one: Humility
¹Possibly Abba Theodorus or Abba Lucianus.