Yahya related to me from Malik from Hisham ibn Urwa from hisfather from A'isha, the wife of the Prophet, may Allah bless him andgrant him peace, that al-Harith ibn Hisham asked the Messenger ofAllah, may Allah bless him and grant him peace, "How does therevelation come to you?" and the Messenger of Allah, may Allah blesshim and grant him peace, said, "Sometimes it comes to me like theringing of a bell, and that is the hardest for me, and when it leavesme I remember what it has said. And sometimes the angel appears to mein the likeness of a man and talks to me and I remember what he says."A'isha added, "I saw it coming down on him on an intenselycold day, and when it had left him his forehead was dripping withsweat."
USC-MSA web (English) reference: Book 15, Hadith 7
Arabic reference: Book 15, Hadith 479