Musannaf Ibn Abi Shayba 21:35

Waki’ narrated to us, from Hisham al-Dastawa’i, from Qatada, from Ibn Abbas, that the Prophet, may Allah bless him and grant him peace, used to say at the time of distress: "There is no god but Allah, the Forbearing, the Generous. There is no god but Allah, Lord of the heavens and Lord of the Great Throne."