Facing a life-or-death situation regarding King Saul's true intentions, David proposes a psychological test to Jonathan. The trial is set against David's planned absence from the upcoming holiday feast, as he will be attending his family's annual sacrifice [רד״ק]. To uncover the truth, David presents two extreme scenarios that will provide a definitive answer. He deliberately ignores middle-ground possibilities—such as Saul not asking about him at all, or asking but showing no reaction—because those outcomes would only leave David in continued doubt [מלבי״ם].
The first scenario focuses on a positive response. If Saul accepts David's absence with understanding and tells Jonathan that he acted correctly in granting him permission [מצודת דוד, ביאור שטיינזלץ], it means David is safe and the king has no plans to kill him [רש״י]. Such a calm reaction is entirely reasonable, given that David's request was respectfully channeled through the king's own son [ביאור שטיינזלץ]. Moreover, Saul would technically have a valid reason to be upset that Jonathan granted this permission independently. Therefore, if the king still chooses to respond favorably despite this, it serves as a solid guarantee and a clear sign of peace [חומת אנך].
The second scenario examines the threat to David's life. If the king becomes angry with David, and even directs his rage at Jonathan for allowing him to leave [חומת אנך], this anger will not be about the missed meal itself. Instead, it will stem from Saul's deep frustration that David is out of his reach, preventing the king from harming or killing him [רש״י, מצודת דוד]. If Saul reacts with such anger, the conclusion is absolute, representing a final and complete end to the matter [מצודת ציון]. It indicates that his dark thoughts have fully crystallized into an unchangeable decision to put David to death [רש״י, מצודת דוד].
Ultimately, this test reveals the depth of the king's hostility. If the simple mention of David's name during a festive, relaxed banquet is enough to trigger a flare-up of bitter anger, it proves that David's fate is sealed. Under such circumstances, he will never find peace as long as Saul is alive [ביאור שטיינזלץ].