שופטים, פרק ח׳, פסוק כ׳

Gideon stands before two captive kings, who are likely bound and entirely helpless, and commands his eldest son to execute them [ביאור שטיינזלץ]. He chooses his firstborn for this specific task for two distinct reasons. First, the son is meant to act as the blood avenger, carrying out justice for the murder of his uncles, Gideon's brothers [מלבי״ם]. Second, Gideon wishes to initiate his son into a life of bravery. Executing two monarchs is considered a great honor, and Gideon views it as a positive sign for the boy's future as a warrior [אברבנאל].

Despite his father's clear instruction, the boy refuses to draw his sword [רש״י]. His hesitation stems from a deep fear tied to his youth, which commentators explain from several angles. Because of his young age, he simply lacks the courage and the necessary hatred to execute men in cold blood [ביאור שטיינזלץ]. Furthermore, his inexperience clouds his judgment. He does not fully grasp that the captive kings are completely at his mercy and unable to fight back, leading him to be physically afraid of them [מצודת דוד]. Ultimately, this reluctance serves as an early sign that the youth will not follow in his father's footsteps to become a mighty warrior capable of conquering kings [אברבנאל].

The boy's inability to act prompts a reaction from the captive kings themselves, who demand that Gideon perform the execution. To the kings, dying at the hands of a weak and inexperienced boy is a deep humiliation. They prefer to fall by the hand of a powerful and proven military commander. This ensures they will meet their end quickly and retain a measure of dignity appropriate for their royal status [אברבנאל].