1 Samuel 20:2

He said, God forbid: thou shalt not die It appears by this that Jonathan knew nothing of his father's design, and that the messengers before named had been sent to seize David without his privity. Hence, from a principle of filial respect to his father, he was very loath to believe that he would do so ill a thing. Behold, my father will do nothing, but he will show it me In this he was greatly mistaken. Communicative as Saul was to his son Jonathan in other things, he was ashamed to disclose to him the wicked design he had formed against the life of his friend. Why should my father hide this thing from me? Why? For an obvious reason; because it was too base and shameful to be discovered to any one that had any fear of God before his eyes, or any sense of moral obligation. He was afraid too that if he should disclose his design to Jonathan, he should find means to prevent its execution. It is not so Jonathan gave credit to his father's oath, mentioned 1 Samuel 19:6.