"A psalm is the tranquility of souls, the arbitrator of peace, restraining the disorder and turbulence of thoughts, for it softens the passion of the soul and moderates its unruliness. A psalm forms friendships, unites the divided, mediates between enemies. For who can still consider him an enemy with whom he has set forth one voice to God? So that the singing of psalms brings love, the greatest of good things, contriving harmony like some bond of union and uniting the people in the symphony of a single choir."
—Saint Basil the Great