Musannaf Ibn Abi Shayba 21:363

Husayn ibn Ali narrated to us, from Za'idah, from Mansur, from Talhah, from Abd al-Rahman ibn Awsajah, from al-Bara' ibn Azib, who said: The Messenger of Allah (may Allah bless him and grant him peace) 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' ten times, it shall be for him equivalent to the freeing of a soul."