"A psalm implies serenity of Soul; it is the author of peace, which calms bewildering and seething thoughts. For, it softens the wrath of the soul, and what is unbridled it chastens. A psalm forms friendships, unites those separated, conciliates those at enmity. Who, indeed, can still consider as an enemy him with whom he has uttered the same prayer to God? So that psalmody, bringing about choral singing, a bond, as it were, toward unity, and joining people into a harmonious union of one choir, produces also the greatest of blessings, love.
A psalm is a city of refuge from the demons; a means of inducing help from the angels, a weapon in fears by night, a rest from the toils of the day, a safeguard for infants, an adornment for those at the height of their vigour, a consolation for the elders, a most fitting ornament for women. It peoples the solitudes; it rids the market places of excesses; it is the elementary exposition of beginners, the improvement of those advancing, the solid support of the perfect, the voice of the Church. It brightens feast days; it creates a sorrow which is in accordance with God. For, a psalm calls forth a tear even from a heart of stone.
A psalm is the work of angels, a heavenly institution, the spiritual incense."
- Saint Basil the Great
Reference: http://www.pravoslavie.ru/english/45167.htm
