Sahih Bukhari
Beginning of Creation
Volume: 004 / Book Number: 054 / Hadith Number: 455
Narrated Abu Ishaq-Ash-Shaibani:
I asked Zir bin Hubaish regarding the Statement of Allah: "And was at a distance Of but two bow-lengths Or (even) nearer; So did (Allah) convey The Inspiration to His slave (Gabriel) and then he (Gabriel) Conveyed (that to Muhammad). (53.9-10) On that, Zir said, "Ibn Mas'ud informed us that the Prophet had seen Gabriel having 600 wings."