Abu Uthman al-Nahdi narrates: It reached me about Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he says: It has reached me that "Allah Almighty grants one of His servants 1000 thousand (i.e. one million) good deeds in return for one good deed." The narrator says: I happened to set out for Hajj or Umrah, and I met Sayyiduna Abu Hurayrah (may Allah be pleased with him). I said: "A report has reached me from you that you say: I heard the Prophet (peace and blessings be upon him) say: 'Allah Almighty grants His believing servant 1000 thousand (i.e. one million) good deeds in return for one good deed.'" Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: "No! Rather, I heard the Prophet (peace and blessings be upon him) say: 'Allah Almighty grants him 2000 thousand (i.e. two million) good deeds.'" Then he recited this verse: "If it is a good deed, He multiplies it and gives from Himself a great reward." Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: "When Allah Almighty has said 'a great reward', then who can estimate its measure?"
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 17188
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه البزار فى المسند (3259) اخرجه احمد فى المسند (521/2) ، أخرجه مسند أحمد برقم: 10381»
In one report the words are: "I came to Sayyiduna Abu Hurayrah (may Allah be pleased with him) and said: 'I have learned that you say: a single good deed becomes 1000 thousand (i.e. a million times).' Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: 'Why are you surprised at this? By Allah, I heard this from the tongue of the Prophet (peace and blessings be upon him).'" After this the narrator mentioned the report as before.
Ahmad recorded it with two chains, and al-Bazzar recorded something similar; the narrators of one of Ahmad's two chains are good.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 17189