Musannaf Ibn Abi Shayba 21:364

Muhammad ibn Ubayd narrated to us, Isma'il narrated to us, from Abu Bakr ibn Hafs, from Abu Du'amah, a man from the Ansar, from Abu al-Darda', who said: "Whoever says one hundred times in a day: 'There is no god but Allah alone, He has no partner, to Him belongs the dominion, to Him belongs the praise, and He is capable of all things,' no one among the people of the world will bring anything better than what he has brought, except for a person who does more than him."