1 Samuel 16:16

And it shall come to pass... thou shalt be well. — It has been a well-known fact in all ages that music exerts a powerful influence on the mind. We have several instances in ancient Greek literature, where this influence is recommended to soothe the passions or to heal mental disease. Pythagoras, whenever he would steep his mind in Divine power, was in the habit before he slept of having a harp played to him; Æsculapius, the physician, would often restore such sick souls with music. (See reference from Censorinus, De die natali, quoted by Keil.)

“Priests would call

On Heaven for aid: but then his brow would lower
With treble gloom. Peace! Heaven is good to all.
To all, he sighed, but one — God hears no prayers for Saul
At length one spake of music.” — HANKINSON.