It is narrated from Hazrat Ka'b (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The souls of the martyrs reside in the form of green birds on the trees of Paradise." It is narrated from Hazrat Ka'b that the Prophet (peace and blessings be upon him) said: "The soul of a Muslim resides in the form of birds on the trees of Paradise, until the Day of Resurrection when Allah Almighty will return it to its body."