Musnad Ahmad 27:542

Yazid narrated to us, Yahya informed us, from Muhammad ibn Yahya, that his paternal uncle, Wasi’ ibn Habban, informed him that he heard Ibn Umar say: "I went up one day onto the roof of our house, and I saw the Messenger of Allah, peace and blessings of Allah be upon him, sitting on two mud bricks, facing Bayt al-Maqdis (Jerusalem)."