Reference : Hisn al-Muslim 254

قَالَ صلى الله عليه وسلم: مَنْ قَالَ (سُبْحَانَ اللَّهِ وَبِحَمْدِهِ) فِي يَوْمٍ مِائَةَ مَرَّةٍ حُطَّتْ خَطَايَاهُ وَلَوْ كَانَتْ مِثْلَ زَبَدِ الْبَحْر.
Allah's Messenger (ﷺ) said: Whoever says:
Subḥānallāhi wa biḥamdihi.
one hundred times a day, will have his sins forgiven even if they are like the foam of the sea.

Allah's Messenger (ﷺ) said: Whoever says:

Glorified is Allah and praised is He.

one hundred times a day, will have his sins forgiven even if they are like the foam of the sea.

Reference:
Al-Bukhari 7/168, Muslim 4/2071, see also invocation no. 91 of this book.

Chapter: Excellence of Tasbih, Tahmid, Tahlil, and Takbir