1 Samuel 20:30-33

Then Saul became very angry with Jonathan. He said, “You son of a wicked, worthless woman! I know you are on the side of David son of Jesse! You bring shame on yourself and on your mother who gave birth to you. As long as Jesse’s son lives, you will never be king or have a kingdom. Now send for David and bring him to me. He must die!” Jonathan asked his father, “Why should David be killed? What wrong has he done?” Then Saul threw his spear at Jonathan, trying to kill him. So Jonathan knew that his father really wanted to kill David.