Musnad Ahmad 31:337

'Abd al-Razzaq narrated to us, he said: Isra'il informed us, from Abu Sinan, from Abu Salih al-Hanafi, from Abu Sa'id al-Khudri and Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him, who said: "Indeed, Allah has chosen four phrases from speech: 'Subhan Allah' (Glory be to Allah), 'Al-hamdu lillah' (Praise be to Allah), 'La ilaha illa Allah' (There is no god but Allah), and 'Allahu Akbar' (Allah is the Greatest). Whoever says: 'Subhan Allah,' twenty good deeds are written for him and twenty bad deeds are removed from him. Whoever says: 'Allahu Akbar,' it is the same as that. Whoever says: 'La ilaha illa Allah,' it is the same as that. And whoever says: 'Al-hamdu lillahi Rabbil-'alamin' (Praise be to Allah, Lord of the worlds) from his own self, thirty good deeds are written for him by it, or thirty bad deeds are removed from him."