The demon is exceedingly envious of a person at prayer and uses every means to ruin this goal. That’s why it never ceases stirring up thoughts about daily affairs through the memory and inciting compulsive desires through the flesh. It does this so that it can impede our progress in our journey out of this country to God.
Whenever that most foul demon is unable, after much trying, to hinder earnest prayer, it withdraws for a short time and then later has its revenge after the end of prayer. It either kindles some sort of anger within you and ruins that excellent and disciplined state that comes from prayer, or seduces you to some irrational pleasure and does violence to your mind.
After you have prayed as you ought, be on your guard against what you ought not to do and stand with courage as you guard your fruit. After all, in the beginning you were commanded “to work and to keep.” So after you have done your work, do not let the result of your labor go unguarded. Otherwise, you’ll have no benefit from your prayer.