Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 379
Narrated Abdullah:
Regarding the Verses: '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) Ibn Mas'ud narrated to us that the Prophet had seen Gabriel with six hundred wings.