"Sahih Muslim (20:4645) - "...He (the Messenger of Allah) did that and said: There is another act which elevates the position of a man in Paradise to a grade one hundred (higher), and the elevation between one grade and the other is equal to the height of the heaven from the earth. He (Abu Sa'id) said: What is that act? He replied: Jihad in the way of Allah! Jihad in the way of Allah!""