Mishkat al-Masabih #2201

Abu Huraira reported God’s messenger as saying that if anyone says a hundred times in a day, “There is no god but God alone who has no partner, to whom dominion belongs, to whom praise is due, who is omnipotent”, he will have a reward equivalent to that for emancipating ten slaves, a hundred blessings recorded for him, a hundred evil deeds obliterated from him; it will be a protection for him from the devil all that day till evening, and no one will bring anything more excellent than he brings, except a man who has done more than he has. (Bukhari and Muslim.)