Musnad Ahmad 26:201

Hajjaj narrated to us, Shareek narrated to us, from ‘Asim, from Abu Wa’il, from ‘Abdullah, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, saw Jibril in his [true] form, and he had six hundred wings. Each wing of them had blocked the horizon. There fell from his wings of wonders, pearls, and rubies, that which only Allah has knowledge of."