What does Isaiah 8:9 mean?
Isaiah's prophecy switches forms from metaphor to overt poetry. It also switches perspectives. He is now looking far beyond the coming destruction in Judah to a time in the future when the Lord will bring the ultimate victory to His people. Despite Judah's current vulnerability, Isaiah boldly shouts out to all the other nations that would threaten God's people. He tells them to be broken and to crumble. This is an invitation to a fight they will lose…eventually.He also calls those enemy nations to prepare themselves for battle against the people of the Lord. He calls for them to prepare their armor. The armor of Isaiah's time included wide belts from which swords and other weapons could hang. As well as breastplates and helmets that were strapped on.
None of it will matter, though. Isaiah tells the nations to prepare to fight a battle they will not win. In other words, no matter how bad things get for God's unfaithful, disobedient people in this moment, they will ultimately be victorious in the Lord. That victory may be far ahead, and there will be much pain for Gods people. Yet Isaiah refuses to be silent about the certainty of this future reality. While not applied to all people, always, it is comforting to know that God's intent is not to let His people suffer forever.