Messenger of Allah ﷺ said, "If a person embraces Islam sincerely, then Allah shall forgive all his past sins, and after that starts the settlement of accounts, the reward of his good deeds will be ten times to seven hundred times for each good deed and one evil deed will be recorded as it is unless Allah forgives it."  

أَخْبَرَهُ أَنَّهُ سَمِعَ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا أَسْلَمَ الْعَبْدُ فَحَسُنَ إِسْلاَمُهُ يُكَفِّرُ اللَّهُ عَنْهُ كُلَّ سَيِّئَةٍ كَانَ زَلَفَهَا وَكَانَ بَعْدَ ذَلِكَ الْقِصَاصُ الْحَسَنَةُ بِعَشْرِ أَمْثَالِهَا إِلَى سَبْعِمِائَةِ ضِعْفٍ وَالسَّيِّئَةُ بِمِثْلِهَا إِلاَّ أَنْ يَتَجَاوَزَ اللَّهُ عَنْهَا  

Messenger of Allah ﷺ said, "If any one of you improve (follows strictly) his Islamic religion then his good deeds will be rewarded ten times to seven hundred times for each good deed and a bad deed will be recorded as it is."  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا أَحْسَنَ أَحَدُكُمْ إِسْلاَمَهُ فَكُلُّ حَسَنَةٍ يَعْمَلُهَا تُكْتَبُ لَهُ بِعَشْرِ أَمْثَالِهَا إِلَى سَبْعِمِائَةِ ضِعْفٍ وَكُلُّ سَيِّئَةٍ يَعْمَلُهَا تُكْتَبُ لَهُ بِمِثْلِهَا