Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said, regarding the saying of Allah Almighty: "He certainly saw of the greatest signs of his Lord" [Surah al-Najm: 18]: "The Prophet (peace and blessings be upon him) saw Jibril (peace be upon him) in his true form; he had six hundred wings, and each one of them filled the space between the east and the west."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9022