Sahih al-Bukhari, Book 80, Hadith 100 (In-Book) ⓘ
Narrated Abu Huraira: Allah's Messenger said, "Whoever says, 'Subhan Allah wa bihamdihi,' one hundred times a day, will be forgiven all his sins even if they were as much as the foam of the sea.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ سُمَىٍّ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنْ قَالَ سُبْحَانَ اللَّهِ وَبِحَمْدِهِ. فِي يَوْمٍ مِائَةَ مَرَّةٍ حُطَّتْ خَطَايَاهُ، وَإِنْ كَانَتْ مِثْلَ زَبَدِ الْبَحْرِ " .
also referenced under: Hadith 6405 (DarusSalam) & Volume 8, Book 75, Hadith 414 (USC-MSA)