God afflicted King Saul’s mind

1 Samuel 16:14–23 (ESV)

14Now the Spirit of the LORD departed from Saul, and a harmful spirit from the LORD tormented him.

15And Saul’s servants said to him, “Behold now, a harmful spirit from God is tormenting you.

16Let our lord now command your servants who are before you to seek out a man who is skillful in playing the lyre, and when the harmful spirit from God is upon you, he will play it, and you will be well.”

17So Saul said to his servants, “Provide for me a man who can play well and bring him to me.”

18One of the young men answered, “Behold, I have seen a son of Jesse the Bethlehemite, who is skillful in playing, a man of valor, a man of war, prudent in speech, and a man of good presence, and the LORD is with him.”

19Therefore Saul sent messengers to Jesse and said, “Send me David your son, who is with the sheep.”

20And Jesse took a donkey laden with bread and a skin of wine and a young goat and sent them by David his son to Saul.

21And David came to Saul and entered his service. And Saul loved him greatly, and he became his armor-bearer.

22And Saul sent to Jesse, saying, “Let David remain in my service, for he has found favor in my sight.”

23And whenever the harmful spirit from God was upon Saul, David took the lyre and played it with his hand. So Saul was refreshed and was well, and the harmful spirit departed from him.

1 Samuel 18:10–11 (ESV)

10The next day a harmful spirit from God rushed upon Saul, and he raved within his house while David was playing the lyre, as he did day by day. Saul had his spear in his hand.

11And Saul hurled the spear, for he thought, “I will pin David to the wall.” But David evaded him twice.

1 Samuel 19:8–10 (ESV)

8And there was war again. And David went out and fought with the Philistines and struck them with a great blow, so that they fled before him.

9Then a harmful spirit from the LORD came upon Saul, as he sat in his house with his spear in his hand. And David was playing the lyre.

10And Saul sought to pin David to the wall with the spear, but he eluded Saul, so that he struck the spear into the wall. And David fled and escaped that night.