Harith bin Hisham asked the Messenger of Allah ﷺ, "How does the revelation come to you?"The Messenger of Allah ﷺ replied, "Sometimes it comes to me like the ringing of a bell, and that is the hardest on me. Then it leaves me, and I have grasped what was said. And sometimes the angel appears to me in the form of a man, speaks to me, and I retain what he says."Ayesha said, "I once saw the revelation descending upon him on a bitterly cold day, and when it left him, his forehead was dripping with sweat."
أن الحارث بن هشام، سأل رسول الله ﷺ: كيف يأتيك الوحي؟ فقال رسول الله ﷺ: أحيانا يأتيني في مثل صلصلة الجرس، وهو أشده علي، فيفصم عني، وقد وعيت ما قال، وأحيانا يتمثل لي الملك رجلا، فيكلمني فأعي ما يقول. قالت عائشة: ولقد رأيته ينزل عليه في اليوم الشديد البرد، فيفصم عنه وإن جبينه ليتفصد عرقا.
Malik narrated it in the Quran (7) from Hisham bin Urwa, from his father, from Ayesha, and he mentioned it. Bukhari narrated it in the beginning of revelation (2) through Malik's route with the same wording. Muslim narrated it in the virtues (2333) through other routes from Hisham bin Urwa, similarly. The other hadiths on this subject are mentioned in the book on revelation.