1 Samuel 19:4-6

And Jonathan spoke well of David to Saul his father and said to him, “Let not the king sin against his servant David, because he has not sinned against you, and because his deeds have brought good to you. For he took his life in his hand and he struck down the Philistine, and the LORD worked a great salvation for all Israel. You saw it, and rejoiced. Why then will you sin against innocent blood by killing David without cause?” And Saul listened to the voice of Jonathan. Saul swore, “As the LORD lives, he shall not be put to death.”