It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) observed: He who intended to do good, but did not do it, one good was recorded for him, and he who intended to do good and also did it, ten to seven hundred good deeds were recorded for him. And he who intended evil, but did not commit it, no entry was made against his name, but if he committed that, it was recorded.
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ، عَنْ هِشَامٍ، عَنِ ابْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ هَمَّ بِحَسَنَةٍ فَلَمْ يَعْمَلْهَا كُتِبَتْ لَهُ حَسَنَةً وَمَنْ هَمَّ بِحَسَنَةٍ فَعَمِلَهَا كُتِبَتْ لَهُ عَشْرًا إِلَى سَبْعِمِائَةِ ضِعْفٍ وَمَنْ هَمَّ بِسَيِّئَةٍ فَلَمْ يَعْمَلْهَا لَمْ تُكْتَبْ وَإِنْ عَمِلَهَا كُتِبَتْ " .
sunnah.com