Prayer is a communion of the mind with God. What sort of state does the mind need so that it can reach out to its Lord without turning back and commune with him without intermediary?Evagrius, On Prayer, 3-4
If Moses, when he tried to approach the earthly burning bush, was held back until he removed the sandals from his feet (Exod. 3: 5), how can you, who wish to see and commune with the one who is beyond all representation and sense perception, not free yourself from every mental representation tied to the passions?
For further elaboration about the imagery of sandals and the passions see this longer piece here Sandals, Death and Communion