Musnad Ahmad 25:1641

Rawh narrated to us, Zakariya ibn Ishaq narrated to us, Amr ibn Dinar narrated to us, that he heard Ikrimah saying: Ibn Abbas used to say regarding {And We did not make the vision which We showed you except as a trial for the people} [Al-Isra: 60]: "It is a matter that the Prophet, peace and blessings of Allah be upon him, was shown while awake; he saw it with his own eyes when he was taken to Bayt al-Maqdis (Jerusalem)."