Musannaf Ibn Abi Shayba 7:152

Muhammad ibn Fudayl narrated to us, from al-‘Ala’, from his father, who said: Ka’b said: "You commit shirk (polytheism)." They said: "And how is that, O Abu Ishaq?" He said: "One of you says: 'No, by my life' (la la-‘amri) and 'By your life' (wa-hayatik)."