Narrated Abu Hurairah:
that the Messenger of Allah (ﷺ) said: "Allah, Blessed and Most High, has said - and His saying is the Truth: 'When My slave considers doing something good then write it as one good for him. If he acts upon it then write ten of the same for him. And when he considers doing something evil, then do not write it. If he acts upon it, then write it. If he leaves it" - and perhaps he said: "if he does not act upon it, then write a good reward for him.'" Then he [the Prophet (ﷺ)] recited: Whoever comes with a good, then he shall have ten the like thereof (6:160).
English reference: Vol. 5, Book 44, Hadith 3073
Arabic reference: Book 47, Hadith 3352