Love of God proceeds from conversing with him; this conversation of prayer comes about through stillness, and stillness comes with the stripping away of the self.
The more wood you pile on a fire the more heat you get, and thus it is with God - the more you think on Him the more you are fired with love and fervor towards Him. He who loves the Lord is always mindful of Him, and remembrance of God begets prayer.
Stillness mortifies the outward senses and resurrects the inward movements, whereas agitation does the opposite, that is, it resurrects the outward senses and deadens the inward movements.