Charles Ellicott Commentary 1 Samuel 19:6

"And Saul hearkened unto the voice of Jonathan: and Saul sware, As Jehovah liveth, he shall not be put to death." — 1 Samuel 19:6 (ASV)

And Saul listened: Jonathan's moving eloquence touched Saul’s heart, and for a short time, something of the old noble spirit influenced the king, and he swore he would not attempt his life.