How Does One Pray in the Heart?

Once a monk from the Holy Mountain who practices the Jesus prayer visited Elder Porphyrios and inquired about how he said the Jesus prayer.  Here is the dialogue that took place:

"How do you say the Jesus Prayer? Do you sit on a stool? Do you lower your head and concentrate?"

"No, " I replied. "I say, 'Lord Jesus Christ...' clearly in my mind giving attention to the words.  'Lord Jesus Christ, have mercy on me... Lord Jesus...' That is how I do it in my mind and pay attention to the words."

"That's not right at all, Elder," he said.  "The way you describe it is quite erroneous, not to say deluded.  The mind needs to be in the heart.  That is why it's called 'prayer of the heart.'"

"I'll tell you something else," I said to him. "Sometimes when I would be facing some temptation, I would bring into my mind the image of the Christ on the cross with his transfixed hands and feet dripping with blood and with the crown of thorns piercing his brow and with myself kneeling before him and saying to Him, 'Lord Jesus Christ, have mercy on me'."

"And you didn't bring your mind into your heart?" he interrupted.

"No." I replied.

"You are deluded," he said to me. "The mind must be in the heart.  That's why it's called 'prayer of the heart.' Delusion!"

He got up to leave.

"Elder!", I said to him. "Listen and I'll tell you something.  When I am repeating the prayer in my mind, sometimes my joy becomes more and more intense.  And when my joy becomes ever stronger with the words, "Lord Jesus Christ...", I feel my mind leaping within me along with my heart. That is, I feel my mind plummeting into my heart and there I experience all this joy as I say the prayer.  I begin with the mind and then my mind moves on its own when when joy comes."

"So that's how you pray! That indeed is the way!" he said to me. "Forgive me for saying 'delusion'."