My brother, start by saying continuously the Jesus Prayer (Lord Jesus Christ, have mercy on me), so this should become a habit for you. You have such a great opportunity to do this here in this lonely place, and in a short while you will be able to obtain great gains by it. No godless thoughts will then be able to get at you, and the true faith and love for Jesus Christ will be revealed to you. You will then understand how the dead will be raised, and you will see the Last Judgment in its true light. The Jesus Prayer will make you feel such relief and blessing in your heart that you will be amazed and your life will be neither gloomy nor troublesome anymore.
From The Way of the Pilgrim
Translated by Dr. Nick Stergiou