Prayer, according to its quality, is communion and union of man with God, by its action it upholds the world. It is reconciliation with God. It is the mother, but also the daughter, of tears. It is the atonement of sins, a bridge over temptations, a wall against affliction, a crushing of conflicts, a work of Angels, the food of the Incoporeal, future gladness, boundless work, source of virtues, cause of grace, invisible progress, food of the soul, illumination of the mind, an axe against despair. a proof of hope, a cure for sorrow, the wealth of monks, the treasure of hesychasts, the reduction of anger, the mirror of progress, the demonstration of stature, an indication of one’s condition, a revelation of future things, a sign of glory. For one who truly prayers, prayer is the court, the judgment hall and the tribunal of the Lord before the judgement to come.
–Saint John Climacus (c. 525-606)