What does Isaiah 9:10 mean?
The people of Israel already had reason to be concerned. They knew about the Assyrian war machine and that it had been pointed towards them (Isaiah 9:9). Had they been smarter, the seemingly inevitable destruction would have terrified them to come. If they had shown any wisdom, they would have turned to the Lord for help in their time of greatest need.Instead, Isaiah describes them as proud and arrogant. He shows them speaking glibly and boastfully about the aftermath of an Assyrian invasion. The prophet quotes them as saying that if the Assyrians knock down their mud-brick homes, they will rebuild with expensive and luxurious stones. And if their enemy cuts down their sycamore or fig trees, they will plant mighty cedar trees in their place. The nation is only calculating a positive for the outcome of this invasion.
In other words, the Israelites were "talking big." They were confident that the coming attack would make them stronger and wealthier in the long run. They put their hope in their own resilience, strength, and opportunism. They underestimated how committed the Lord was to bringing them to their knees. Their faithlessness and disobedience to Him would not continue unpunished.
Israel soon learn that the destruction to come would leave no room for an improved life through hard work and self-reliance. Without the Lord on their side, they would be wiped off the map (Isaiah 7:8)