From Sahih Bukhari (Hadith 3232):
Narrated Abu 'Is-haq-Ash-Shaibani:I asked Zir bin Hubaish regarding the Statement of Allah: "And was at a distance Of but two bowlengths 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 (ﷺ) had seen Gabriel having 600 wings
Reference: Bukhari 3232