It is narrated from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever, on finishing the Fajr prayer and before speaking, says these words ten times: 'La ilaha illallahu wahdahu la sharika lah, lahul-mulku wa lahul-hamd, biyadihil-khayr, wa huwa 'ala kulli shay'in qadir' (There is no god worthy of worship except Allah, alone, without partner; His is the dominion and His is the praise; in His hand is good, and He has power over all things), is given seven (rewards) in return for them: ten good deeds are written for him, ten sins are erased from him, he is raised ten ranks, they are for him equal to freeing ten souls, they are for him a protection from the devil and a safeguard from every harm, and no sin overtakes him that day except associating partners with Allah. And whoever says them on finishing the Maghrib prayer is given one third of that."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17255