The Messenger of Allah ﷺ said, "When one of you perfects his Islam, every good deed he performs is recorded as ten of its like, up to seven hundred times, and every bad deed he commits is recorded as one of its like, until he meets Allah."
قال رسول الله ﷺ: إذا أحسن أحدكم إسلامه، فكل حسنة يعملها تكتب بعشر أمثالها إلى سبع مئة ضعف، وكل سيئة يعملها تكتب بمثلها حتى يلقى الله.
Bukhari narrated it in the Book of Faith (42), and Muslim narrated it in the Book of Faith (129:205), both through the route of Abdul-Razzaq, who said, Mamar told us, from Hammam bin Munabbih, from Abu Hurairah, who mentioned it.