"Authentic prayer - the warmth that accompanies the Jesus Prayer, for it is Jesus who enkindles fire on the earth of our hearts (Luke 12:49) - consumes the passions like thorns and fills the soul with delight and joyful ness. Such prayer comes neither from right nor left, nor from above, but wells up in the heart like a spring of water from the life-quickening Spirit. It is this prayer alone that you should aspire to realise and possess in your heart, always keeping your intellect free from images, concepts and thoughts. And do not be afraid, for he who says, "Take heart; it is I, be not afraid" (Matthew 14:27), is with us - he whom we seek and who protects us always. When we invoke God we must be neither timid nor hesitant."
St. Gregory of Sinai: On Prayer
Gregory reminds us that the Jesus Prayer should be imageless. Also, he says, don't be timid in your praying for we have received the Spirit of God making us children of God (see Romans 8:14-16)