Musnad Ahmad 593:1

Rawh narrated to us, Hammam narrated to us, Abdullah ibn Abi Husayn al-Makki narrated to us, from Shahr ibn Hawshab, from Abd al-Rahman ibn Ghanam, from the Prophet, may Allah bless him and grant him peace, that he said: "Whoever says, before he turns away and folds his leg from the Maghrib and Subh prayer: 'There is no god but Allah, alone, with no partner; to Him belongs the dominion, and to Him belongs the praise; in His hand is all good; He gives life and causes death, and He is capable of all things,' ten times, there shall be written for him for each one ten good deeds, and ten evil deeds shall be erased from him, and he shall be raised ten degrees. It shall be a protection for him from every disliked thing, and a protection from the accursed Satan. No sin shall be permissible for him to encounter except shirk (associating partners with Allah). And he shall be among the best of people in deeds, except for a man who surpasses him by saying something better than what he said."