Be constant in your practice, and one day the One who gave you the desire for the prayer of the heart will give you that prayer itself. When your heart's intention is fixed on God, it will keep lit the incense of your prayer, and wind of distraction will not put it out. do not worry about stray thoughts; they may come and go, but they will not take your attention away from God.
Fire is an intimate force. Whereas light is very heartening, it remains quite superficial. It touches only the surface of things. ...Fire, on the other hand, has the power to penetrate to the very essence of substance. Fire can go to the heart of the matter.