Musnad Ahmad 28:264

Hassan narrated to us, Hammad ibn Salamah narrated to us, from Thabit al-Bunani and Dawud ibn Abi Hind, from ‘Amr ibn Shu‘ayb, from his father, from his grandfather, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever says: 'There is no god but Allah, alone, with no partner, to Him belongs the dominion, and to Him belongs the praise, and He is capable of all things' (La ilaha illallah, wahdahu la sharika lah, lahul-mulku wa lahul-hamd, wa huwa ‘ala kulli shay’in qadir), two hundred times every day, no one who came before him will surpass him, and no one who comes after him will overtake him, except for one who does better than his deed."