Sahih Muslim, Chapter: Faith (Kitab Al Iman)

I said to Aisha: What about the words of Allah: "Then he drew nigh and came down, so he was at a distance of two bows or closer still: so He revealed to His servant what He revealed" (al-Quran, liii. 8-10)? She said: It implies Gabriel. He used to come to him (the Holy Prophet) in the shape of men; but he came at this time in his true form and blocked up the horizon of the sky.