Sahih Bukhari Volume 4, Book 54, Hadith Number 455.

Narated By 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.”