The great battles of the spiritual war are noetic, that is, battles of the mind and heart.  Learn to pray with watchfulness and without distraction born of passions. In this brief but penetrating text, which opens the majestic patristic literary collection the Church known as the Philokalia, St. Isaiah the Solitary guides the believer in the effort to purify the mind and heart, sanctify and adhere to the conscience, and learn to pray with watchfulness and without distraction born of passions.