Musnad Ahmad 1153:1493

'Ali ibn 'Asim narrated to us, he said: Khalid al-Hadhdha' informed me, from Khalid ibn Abi al-Salt, he said: I was with 'Umar ibn 'Abd al-'Aziz during his caliphate—he said: And 'Arak ibn Malik was with him—so 'Umar said: "I have neither faced the Qiblah nor turned my back to it while urinating or defecating since such and such a time." 'Arak said: 'Aishah narrated to me, "That when the statement of the people regarding that reached the Messenger of Allah (may Allah bless him and grant him peace), he ordered his seat to be turned to face the Qiblah."