Narrated Masruq:
from 'Abdullah that he was asked about Allah's saying: Think not of those as dead who are killed in the way of Allah. Nay they are alive, with their Lord (3:169). So he said: "As for us, we asked about that, and we were informed that their souls are in green birds wandering in Paradise wherever they wish, returning to lamps hanging from the Throne. Your Lord looks at them and says: 'Do you want anything more that We may grant you more?' They say: 'Our Lord! What more could we have when we are in Paradise wandering wherever we want' Then He looks at them a second time and says: "Do you want anything more that We may grant you more?' When they realize that they will not be left alone with that, they say: 'Return our souls to our bodies, so that we may return to the world to be killed in Your cause another time.'"
English reference: Vol. 5, Book 44, Hadith 3011
Arabic reference: Book 47, Hadith 3282