The רד״ק points out that at this point David must have been in Saul’s good graces, even if David had to flee from ניות initially. He returned to Givat Shaul to talk with Jonathan and as we see later, he was an honored guest at Saul’s table. After Saul’s נבואה, his paranoia went into remission. Temporarily.
Swear Words
Jonathan refuses to believe that his father would try to hurt David; מלבי״ם explains אין זאת as לא להרגך צוה לשמרך רק בהפך לשמרך שלא תברח מלפניו. Saul sent for you at your home with Michal and when you were with Shmuel only for your protection. David has to swear that he is telling the truth before Jonathan believes him. רד״ק explains that Saul had previously sworn never to hurt David. Both David and Saul are צדיקים; there’s no reason either one should lie. Surely David is just misinterpreting the evidence.
And we can hear the resignation and sadness in Jonathan’s voice as he asks, מה תאמר נפשך ואעשה לך. So David proposes a test: tomorrow is ראש חדש, the occasion of a state dinner, and it would be lèse-majesté not to be there. I will provoke him so we can tell what he really feels.
Artscroll Tehillim cites the Mishbetzos Zahav that אם כה יאמר טוב may mean not only that Saul is saying “Fine, David can go”, but “Good that David is gone”; it may indicate that Saul realizes he is not well and may lose control and strike out at David and it is better that David not be there. In that case as well that would be שלום לעבדך; David could deal with that.
David protests again that he has not done anything wrong; “If I have sinned, don’t play games with me to bring me back to your father: kill me yourself”. So Jonathan has to protest his innocence. But David still isn’t sure how to get the results back to him without betraying himself to Saul’s spies.
The phrase כלתה הרעה מעמו is unusual; כלה usually means “ended, destroyed” but here it means “finalized, decided”. We see the same use in מגילת אסתר:
The Walls Have Ears
Jonathan at least realizes that there is potentially some danger, and has them continue the conversation out of earshot. He then agrees to the plan but asks for one more day (David wanted to hide עד הערב השלשית; Jonathan will test his father כעת מחר השלשית) and he is still sure that things will turn out well: הנה טוב אל דוד. But even if Saul does wish you ill (ייטב אל אבי את הרעה עליך) I will let you know and allow you to go in peace.
The rest of the paragraph is difficult to parse (five ולא's in 2 psukim!). I would read it the way מלבי״ם does: I acknowledge that you will be king (ויהי ה׳ עמך כאשר היה עם אבי). The usual thing for a new king to do in a contested monarchy is to kill off all his rivals and their entire families. But in our case, I adjure you: may it not be the case that [if I am still alive when you become king and you do not (have mercy on me and not kill me)]. In other words, if I am alive when you become king, don’t kill me. And don’t destroy my family, even when all your enemies are destroyed (פסוק טו).
And Jonathan makes it a covenant (a two-sided agreement) by promising to protect David’s family from Saul’s wrath.