What is the extent of the fear of God?

St. Philoxenus of Mabbug often focuses on the internal dimension of our fear of the Lord, saying, “In this way only may the spiritual soldier fear God, not like servants fearing [their] lords or subjects [fearing their] kings and judges. Fear puts on those outer demeanors and is visible on the outside on the members of the body, and when it happens that they hate them inwardly and despise them with their thoughts, they are showing them on the outside a garment of fear. May your own fear of God not be like this, but from wherever [God] is observing, from there show this fear. Wherever [God] sees secretly the movements of your soul, may the power of his fear take hold of you. Fear God absolutely, fully, in your interior [person] and in your exterior [person], for he is the judge of your secret and public actions. May your soul be ashamed before him and not sin, and may your thought be modest and not commit iniquity … But you should remember at all times that God is watching you, and you should observe him also secretly—That One who sees you secretly—and sin will not remain in your thoughts … But when you are alone by yourself, and the walls of the house and the roof shelter you on all sides, here the armor of the fear of God is necessary for you, because in darkness sin is easily accomplished. Here you ought to alert your soul to the memory of God.”³⁸⁷