And it came to pass, when the evil spirit from God was upon Saul, that David took a harp, and played with his hand: so Saul was refreshed, and was well, and the evil spirit departed from him.
All Commentaries on 1 Samuel 16:23 Go To 1 Samuel 16
Gregory of Nyssa
AD 394
Once when he came to Saul, who was frenzied and out of his right mind, he healed him by soothing his passions with song, so that Saul’s understanding returned to him again in accordance with nature. The goal, then, of the symbolism of the singing is clear from these words. It recommends that we achieve the subjugation of those passions which arise in us in various ways from the circumstances of life.