A dramatic warning is issued to the Israelites, urging them to closely observe the political shifts occurring in the world around them. They are called to pay deep, focused attention to the normal balance of power and the standard ways in which nations typically conquer one another [מצודת דוד, המלבי״ם, אברבנאל]. Through this intense and careful observation [המלבי״ם], the people must ask themselves if they have ever heard of the type of phenomenon that is about to unfold [אבן עזרא].
This careful observation is meant to prepare them for a profound shock and deep amazement at the great devastation Nebuchadnezzar will soon bring [רד״ק]. The core reason for this overwhelming shock is the realization that God Himself is actively directing these historical events [אבן עזרא, רד״ק, ביאור שטיינזלץ]. Furthermore, this is not a distant threat reserved for some future era, but a harsh reality already beginning to unfold in their very own generation [רד״ק, המלבי״ם].
The specific event God is orchestrating is the sudden rise of an exceptionally cruel nation, the Chaldeans. This nation is so thoroughly destructive that God, as it were, regrets ever creating them [רש״י]. The rapid ascent of their leader, Nebuchadnezzar, completely defies all natural logic. A man entirely lacking royal lineage will elevate himself, conquer the entire world without facing any meaningful opposition, and rule with absolute, unchallenged power [אברבנאל].
The sheer magnitude of this global upheaval is incomprehensible. If the Israelites were merely told about it, they would never believe such a scenario was possible, as it entirely contradicts the standard laws of nature and human logic [מצודת דוד, המלבי״ם, מצודת ציון]. Because this prophecy was delivered before the destruction of Jerusalem, the prophet knew perfectly well that his contemporaries would hear his warnings and stubbornly refuse to believe them. Only when they are forced to live through this cruel reality and witness it with their own eyes will they finally understand the truth and be struck with absolute amazement [אברבנאל].