In moments of deep anxiety, David fears for his life and needs a safe way to discover King Saul's true intentions. Jonathan proposes a plan to pass this crucial information without arousing suspicion, taking advantage of the royal feast scheduled for the very next day [אברבנאל, מצודת דוד]. Because the test is set for the start of the new month, it can begin immediately without any agonizing delay [אלשיך]. The choice to test the king's attitude specifically on the new moon is highly deliberate, designed to strip away any ordinary excuses for David's absence. On a regular weekday, Saul might simply assume that David is fasting or that he is ritually impure and therefore unable to attend. However, fasting is forbidden on the new moon, and everyone is required to purify themselves for the festive meal. Beyond removing excuses, this specific timing serves a deeper diagnostic purpose. It will reveal whether Saul's hostility stems from the evil spirit that occasionally torments him, or from a conscious, deeply held personal grudge. Since the evil spirit has no power on holy days like the new moon or the Sabbath, whatever reaction Saul displays will be a pure reflection of his true will [אהבת יהונתן].
During this feast, David's absence will be glaringly obvious, as it is customary for all regular guests to join the royal table on a festival [רש״י, אברבנאל]. Anticipating the king's reaction, Jonathan notes two complementary outcomes: the king will actively notice David is missing and ask about him, and he will do so precisely because David's seat remains physically empty [רש״י, רד״ק, מצודת ציון, ביאור שטיינזלץ]. The reason the seat will stay completely vacant is directly tied to David's unique status. Everyone in the court knows that David is destined to take the throne after Saul, meaning no one else will dare to sit in his place. This glaringly empty chair, with no one willing to fill the void, will easily be interpreted as a silent act of rebellion. Consequently, it is expected to provoke the king's anger and fully expose his true feelings toward David [אהבת יהונתן].
Understanding that this empty seat will inevitably force the truth into the open, Jonathan finalizes the plan by establishing a secret signal using arrows. To any observer, Jonathan's actions will look like nothing more than innocent archery practice. By shooting the arrows off to the side rather than aiming at a specific target, he ensures that his young servant will not suspect a thing. Through this simple deception, Jonathan will safely deliver the fateful message to David as he waits in hiding [אלשיך].