قَالَ صلى الله عليه وسلم مَنْ قَالَ: سُبْحَانَ اللَّهِ وَبِحَمْدِهِ فِي يَوْمٍ مِائَةَ مَرَّةٍ حُطَّتْ خَطَايَاهُ وَلَوْ كَانَتْ مِثْلَ زَبَدِ الْبَحْر)).
(Whoever says:(How perfect Allah is and I praise Him.) a hundred times during the day, his sins are wiped away, even if they are like the foam of the sea.)
Al-Bukhari 7/168, Muslim 4/2071, see also invocation no. 91 of this book.