Musannaf Ibn Abi Shayba 21:170

Hassan ibn Musa narrated to us, from Hammad ibn Salamah, from Suhayl, from his father, from Abu Ayyash al-Zurqi, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever says when he reaches the morning: '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,' it is for him equivalent to the freeing of a slave from the children of Ishmael. Ten good deeds are written for him because of it, ten evil deeds are removed from him because of it, ten degrees are raised for him because of it, and he is in a sanctuary from Satan until he reaches the evening. And when he reaches the evening, it is the same until he reaches the morning."