1 Samuel 19:4-6

Then Jonathan spoke well of David to Saul his father and said to him, “May the king not sin against his servant David, since he has not sinned against you, and since his deeds have been very beneficial to you. For he took his life in his hand and killed the Philistine, and the LORD brought about a great victory for all Israel; you saw it and rejoiced. Why then would you sin against innocent blood by killing David without a cause?” Saul listened to Jonathan and swore [an oath], “As the LORD lives, he shall not be put to death.”