8. When the mind, taking refuge in Christ and calling upon Him, stands firm and repels its unseen enemies, like a wild beast facing a pack of hounds from a good position of defence, then it inwardly anticipates their inner ambuscades well in advance. Through continually invoking Jesus the peacemaker against them, it remains invulnerable.
28. It is impossible to find the Red Sea among the stars or to walk this earth without breathing air; so too it is impossible to cleanse our heart from impassioned thoughts and to expel its spiritual enemies without the frequent invocation of Jesus Christ.
29. Be watchful as you travel each day the narrow but joyous and exhilarating road of the mind, keeping your attention humbly in your heart, reproaching yourself, ready to rebut your enemies, thinking of your death and invoking Jesus Christ. You will then attain a vision of the Holy of Holies and be illumined by Christ with deep mysteries. For in Christ ‘the treasures of wisdom and knowledge’ are hidden, and in Him ‘the fulness of the Godhead dwells bodily.’ In the presence of Christ you will feel the Holy Spirit spring up within your soul. It is the Spirit who initiates man’s intellect, so that it can see with ‘unveiled face.’ For ‘no one can say “Lord Jesus” except in the Holy Spirit.’ In other words, it is the Spirit who mystically confirms Christ’s presence in us.
St. Hesychios the Priest, On Watchfulness and Holiness