The Prayer of Jesus is the chief weapon of the Remnant that must be fought in the battleground of (for) the heart, the method is to invoke the Name of Jesus over and over again in the heart, as flashes of lightning appear in the sky before the rain (Joel ).
The Name of Jesus is the lightning flash which, when repeated in the sky of the heart (the nous), induces the healing rain of Divine grace to water the "earth of the heart". (i.e. the nous, mind is the sky of the earth or the heart, the sky coming down to the earth with the lightning of the Holy Name invoked and as the sky delivers this rain, the earth (heart) opens to receive and there the Name is invoked by the heart. (MLP 1:158).
Furthermore the heart is truly a cosmos: sky, atmosphere, rain, earth, fruit producing, all pointing to the existence of life, as with the earth, only the heart has life.