Saul listened to the voice of Jonathan: and Saul swore, As Yahweh lives, he shall not be put to death.
Jonathan’s appeal was successful, at least temporarily, and resulted in Saul solemnly vowing not to kill David (1 Samuel 19:6), which vow he broke shortly (1 Samuel 19:10). Later Jonathan was not as successful (1 Samuel 20:28-29). Nevertheless this time his appeal resulted in David’s restoration to the court and his continuing ministry to the king (1 Samuel 19:7).