19So Saul sent messengers to Jesse and said, “Send me your son David, who is with the sheep.”
20And Jesse took a donkey loaded with bread, a skin of wine, and one young goat, and sent them to Saul with his son David.
21When David came to Saul and entered his service, Saul admired him greatly, and David became his armor-bearer.
22Then Saul sent word to Jesse, saying, “Let David remain in my service, for I am pleased with him.”
23And whenever the spirit from God came upon Saul, David would pick up his harp and play, and Saul would become well, and the spirit of distress would depart from him.
— 1 Samuel 16:19-23

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Devo: Spiritual Warfare

"When the evil spirit from God, troubled Saul, David would take his harp and play. Then the evil spirit would leave him, and Saul would feel better."