Saul listened to the voice of Jonathan and swore an oath: “As surely as the LORD lives, David will not be put to death.”
Saul and Jonathan appear here in their different characters, with reference to David. I. Never was enemy so unreasonably cruel as Saul. He spoke to his son and all his servants that they should kill David, Sa1 19:1. His projects to take him off had failed, and therefore he proclaims him an out-law, and charges all about him, upon their allegiance, to take the first opportunity to kill David.
Commenting on 1 Samuel 19:1-7
And Saul hearkened unto the voice of Jonathan,.... Not only heard him out what he had to say, but was affected with it, and wrought upon by it, and was convicted for the present that he was wrong in seeking the life of David, and therefore would desist from it; the Lord working upon his mind by what Jonathan said, and inclined him to listen...
And Saul hearkened unto the voice of Jonathan: and Saul sware, [As] the LORD liveth, he shall not be slain. (c) Whatever he pretended outwardly, yet his heart was full of malice.