1 Samuel 16:14

Then God sent an evil spirit between Abimelech and the lords of Shechem; and the lords of Shechem dealt treacherously with Abimelech,

And she said, “The Philistines are upon you, Samson!” And he awoke from his sleep and said, “I will go out as at other times and shake myself free.” But he did not know that Yahweh had left him.

Thus it happened that whenever the evil spirit from God came to Saul, David would take the harp and play it with his hand; and Saul would be refreshed and be well, and the evil spirit would depart from him.

Now it happened on the next day that an evil spirit from God came mightily upon Saul, and he raved in the midst of the house. Now David was playing the harp with his hand, as usual; and a spear was in Saul’s hand.

And Saul was afraid of David, for Yahweh was with him but had turned away from Saul.

Now there was an evil spirit from Yahweh on Saul as he was sitting in his house with his spear in his hand, and David was playing the harp with his hand.

Then Samuel said to Saul, “Why have you disturbed me by bringing me up?” And Saul answered, “I am greatly distressed, for the Philistines are waging war against me, and God has turned away from me and no longer answers me, either by the hand of the prophets or by dreams; therefore I have called you, that you may make known to me what I should do.”

but My lovingkindness shall not be removed from him, as I removed it from Saul, whom I removed from before you.

“And Yahweh said to him, ‘How?’ And he said, ‘I will go out and be a lying spirit in the mouth of all his prophets.’ Then He said, ‘You shall entice him and also prevail. Go out and do so.’

David Becomes Saul’s Armor Bearer