It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that he said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is grieved by his evil deed (i.e. finds his evil deed displeasing), he is a believer."
No one narrated this hadith from Muhammad bin al-Hanafiyyah (may Allah have mercy on him) except Muhammad bin Ka'b (may Allah have mercy on him), and no one from Muhammad bin Ka'b (may Allah have mercy on him) except Musa bin Ubaydah (may Allah have mercy on him), and Abdullah bin Abi Ja'far (may Allah have mercy on him) is alone in it.
Hadith Referenceالمعجم الأوسط / باب الميم / 7474
Hadith Gradingمحدثین:إسناده ضعيف جدًّا، فيه موسى بن عبيدة
Hadith Takhrij«قال الهيثمي: فيه موسى بن عبيدة وهو هالك في الضعف «مجمع الزوائد ومنبع الفوائد، ج 1، ص 86»»