(6) باب ذِكْرِ الْمَلاَئِكَةِ
Narrated Aisha:
Al Harith bin Hisham asked the Prophet, "How does the divine inspiration come to you?" He replied, "In all these ways: The Angel sometimes comes to me with a voice which resembles the sound of a ringing bell, and when this state abandons me, I remember what the Angel has said, and this type of Divine Inspiration is the hardest on me; and sometimes the Angel comes to me in the shape of a man and talks to me, and I understand and remember what he says."
Reference: Sahih al-Bukhari 3215
In-book reference: Book 59, Hadith 26
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 54, Hadith 438