The Jesus Prayer can be strong medicine in the battle against our passions, but it must be applied to the source of our illness. It does no good to treat a stomach ache by applying ointment to the surface of the skin; so too is it ineffective to say the Jesus Prayer with inattention or a distracted mind. To fight our passions with this prayer—to combat sadness, or anger or sinful thoughts with it—requires that it be applied deep into our heart, the place of these illnesses, and this necessitates vigilant and focused prayer, developed with effort and mental focus over time.
~FS
Prayerful Life 