The person who has attained purity of heart has triumphed over cowardice. The person still in the process of being purified sometimes overcomes it and sometimes is overcome by it. The person not even engaged in spiritual warfare is either completely unaware that he is the ally of his own passions and of the demons and that he is sick with pride and presumption, thinking he is something when he is not; or else he is the slave and servant of cowardice, trembling like a baby and fearing fear where, for those who fear the Lord, there is no fear (Psalm 14:5 LXX) nor any occasion for cowardice.
~St Symeon the New Theologian
Prayerful Life 