When remembrance of God lives in the heart and there maintains the fear of Him, then all goes well; but when this remembrance grows weak or is kept only in the head, then all goes astray.
The Jesus Prayer is not some talisman. Its power comes from faith in the Lord, and from a deep union of the mind and heart with Him. With such a disposition, the invocation of the Lord’s Name becomes very effective in many ways. But a mere repetition of the words does not signify anything.
You regret that the Jesus Prayer is not unceasing, that you do not recite it constantly. But constant repetition is not required. What is required is a constant aliveness to God — an aliveness present when you talk, read, watch, or examine something. But since you are already practising the Jesus Prayer… in due course the prayer will widen its scope.