Sayyiduna al-Harith bin Hisham (may Allah be pleased with him) says: I asked the Messenger of Allah (peace and blessings be upon him): How does (the revelation) come to you? He (peace and blessings be upon him) said: Sometimes the revelation comes to me like the sound of a bell; sometimes the angel comes to me in the form of a man and speaks with me, and that form is easier for me. When this state ends, I have already retained what was said.
Al-Tabarani recorded it with two chains, and the narrators of one of them are thiqat (trustworthy).