Delivering a divine message to a hostile audience demands extraordinary mental fortitude. To ensure the prophet does not break under the pressure of his opponents, God grants him absolute inner resilience. The prophet is assured that his spiritual strength will overpower the stubbornness of the people. This divine reinforcement is illustrated through a powerful comparison involving a unique cutting force acting upon solid rock or flint [מצודת ציון, רד"ק]. While commentators debate the exact nature of this force, they agree on its function. Some describe it as a miraculous worm or creature capable of slicing through stone simply by being presented before it [רש"י, ביאור שטיינזלץ]. Others understand it to be a massive boulder [רש"י], exceptionally strong iron [רש"י, מצודת ציון, רד"ק], or another remarkably hard material [ביאור שטיינזלץ].
Regardless of its physical identity, the purpose of the imagery is clear. Just as this force cuts through the hardest stone, God hardens the prophet's resolve to be firmer than the stubbornness of the people, allowing him to shatter their resistance and put them to shame [מצודת דוד, רד"ק]. A unique perspective notes that this cutting force is actually weak on its own, yet it possesses a supernatural ability to split rocks. In the same way, the prophet will overcome his adversaries not through his own natural physical might, but through a special divine quality implanted within him [מלבי"ם].
Armed with this divine reinforcement, the prophet is commanded to stand fearless. He must not be intimidated by any potential harm, nor should he feel inferior or insignificant, even if his opponents are numerous and highly respected [מלבי"ם]. God provides him with all the necessary strength to confront them [ביאור שטיינזלץ]. God is fully aware that the people will fiercely oppose the prophet when he rebukes them [רד"ק]. However, because they are deeply rebellious, they are entirely unworthy of his fear or respect [ביאור שטיינזלץ]. Ultimately, their status as a rebellious house means that while they will certainly resist, their opposition is futile; it will completely dissolve before the prophet, and they will fail to cause him any real harm [מלבי"ם, מצודת דוד].