Musannaf Ibn Abi Shayba 3:5058

Waki' narrated to us, he said: Isra'il narrated to us, from 'Abd al-A'la, from 'Amir al-Sha'bi, from Abu 'Abd al-Rahman al-Sulami, from 'Ali, he said: "What is between the East and the West is a Qibla."