Sahih Muslim 2687
Sahih Muslim · Book 48: The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness · The Virtue Of Remembrance, Supplication, Drawing Close To Allah And Thinking Positively Of Him
A hadith like this has been transmitted on the authority of A'mash with the same chain of transmitters and he (further) said:
حَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، بِهَذَا الإِسْنَادِ . نَحْوَهُ غَيْرَ أَنَّهُ قَالَ " فَلَهُ عَشْرُ أَمْثَالِهَا أَوْ أَزِيدُ " .
There is for him ten like that (the good he performed) or more than that.