1 Samuel 20:30-33

30Saul boiled with rage at Jonathan. “You stupid son of a whore!” he swore at him. “Do you think I don’t know that you want him to be king in your place, shaming yourself and your mother?

31As long as that son of Jesse is alive, you’ll never be king. Now go and get him so I can kill him!”

32“But why should he be put to death?” Jonathan asked his father. “What has he done?”

33Then Saul hurled his spear at Jonathan, intending to kill him. So at last Jonathan realized that his father was really determined to kill David.