Sahih Muslim 2691
The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness
The Virtue Of Tahlil (Saying La Ilaha Ill-Allah), Tasbih (Saying Subhan Allah) And (Du'a) Supplication
Abu Huraira reported Allah's Messenger (ﷺ) as saying: He who uttered these words:" There is no god but Allah, the One, having no partner with Him. Sovereignty belongs to Him and all the praise is due to Him, and He is Potent over everything" one hundred times every day there is a reward of emancipating ten slaves for him, and there are recorded hundred virtues to his credit, and hundred vices are blotted out from his scroll, and that is a safeguard for him against the Satan on that day till evening and no one brings anything more excellent than this, except one who has done more than this (who utters these words more than one hundred times and does more good acts) and he who utters:" Hallowed be Allah, and all praise is due to Him," one hundred times a day, his sins are obliterated even if they are equal to the extent of the foam of the ocean.