The Messenger of Allah ﷺ said, "Whoever says, 'There is no god but Allah alone, with no partner. To Him belongs the dominion and to Him belongs all praise, and He is capable of all things,' one hundred times, it will be equivalent to freeing ten slaves, one hundred good deeds will be recorded for him, one hundred bad deeds will be erased from him, and it will be a protection for him from Satan that day until evening. No one will come with anything better than what he has brought, except a man who has done more than that. And whoever says one hundred times in a day, 'Glory be to Allah and praise be to Him,' his sins will be wiped away even if they were like the foam of the sea."
حدثنا إسحاق بن عيسى أنبأنا مالك عن سمي عن أبي صالح
قال رسول الله ﷺ من قال لا إله إلا الله وحده لا شريك له له الملك وله الحمد وهو على كل شيء قدير مائة مرة كانت له عدل عشرة رقاب وكتبت له مائة حسنة ومحيت عنه مائة سيئة وكانت له حرزا من الشيطان يومه ذلك حتى يمسي ولم يأت أحد أفضل مما جاء به إلا امرؤ عمل أكثر من ذلك ومن قال في يوم مائة مرة سبحان الله وبحمده مائة مرة حطت خطاياه وإن كانت مثل زبد البحر
Its isnad is sahih. It previously occurred at 2/302 of the printed edition. (2) "a hundred times": omitted from H because it is a repetition.