Musnad Ahmad 27:159

'Abdah narrated to us, 'Ubaydullah narrated to us, from Muhammad ibn Yahya ibn Habban, from his paternal uncle, Wasi', from Ibn 'Umar, who said: "I climbed one day onto the roof of Hafsah's house, and I saw the Messenger of Allah, peace and blessings of Allah be upon him, attending to his need, facing Ash-Sham (the Levant) and turning his back to the Qiblah."