Hadith 104
قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " إِذَا أَحْسَنَ أَحَدُكُمْ إِسْلامَهُ، فَكُلُّ حَسَنَةٍ يَعْمَلُهَا تُكْتَبُ بِعَشْرِ أَمْثَالِهَا إِلَى سَبْعِ مِائَةِ ضِعْفٍ، وَكُلُّ سَيِّئَةٍ يَعْمَلُهَا تُكْتَبُ لَهُ بِمِثْلِهَا حَتَّى يَلْقَى اللَّهَ عَزَّ وَجَلَّ "
And the Messenger of Allah, peace and blessings be upon him, said: "When any one of you makes his Islam good (through righteousness and obedience), then every good deed that he performs is written for him as ten to seven hundred times (its reward), and every sin that he commits is written as only one sin. This continues until he meets Allah, the Exalted."