1 Samuel 16:21-23

21Then David came to Saul and became one of his attendants. Saul loved him greatly, so David became his armor-bearer.

22Then Saul sent word to Jesse saying, “Let David now keep attending me, for he has found favor in my eyes.”

23It came to pass, whenever the spirit from God came upon Saul, David would take the harp and play it with his hand. So Saul would find relief and feel better, as the evil spirit departed from him.