In these first five chapters, God through Isaiah called His People to account for their sins. Here Jehovah delivers His verdict against the sins of Israel and Judah. Standing like any servant before a king, lacking any word of defense, there is left only a thorough run down of the full measure of penalty.
It serves well to keep in mind any nation could have found the favor of God by applying their best understanding of the Covenant of Noah. Going the extra mile with Israel, the Lord delivered a fully explicated suzerain treaty to His vassal nation. In extravagant detail, He laid out a specific application of Noah through Moses. It was fully consistent with already established cultural practices of these people, and included generous allowances for restoring the covenant when things simply didn't work out right.
The purpose was to permit Him to show through mere human government what He required of all nations. Had Israel done half the job, it would have pointed all mankind by example to the higher spiritual realities of faith and personal redemption from the Sin which held all in thrall. Not only did Israel herself quickly lose sight of that eternal spiritual truth, but could not even bring herself to obey well enough to reap the worldly benefits available to all humanity.
The indictment against the nation begins with the Parable of the Vineyard. Having done all He could do to make her fruitful, Israel refused to produce even the pitiful fruit of human success. What would any man do in such a case? Return it to its natural state, for it is rightly wilderness land, unworthy of cultivation. Israel was a spiritual wilderness, as well as a civil and social wilderness. Just to ensure no one misses it, Isaiah points the finger of accusation at the whole nation of Israel: "You are the pampered vineyard which brought no useful fruit!"
We can identify six points of failure noted in this sentence.
First, there is the greed which destroys the community. It's one thing to pile up gold and other portable possessions. It harms no one if you prosper in that fashion. When you turn your prosperity into a weapon to dispossess families from the source of maintaining life on the earth, you condemn them unjustly to starvation. Using financial and legal leverage to amass power is, by definition, sin. In this case, it is the power to exclude others from any hope of surviving, much less prospering as God had planned. Further, it creates a barrier between a small elite landowner class treading down a nation of peasants. This breaks the Covenant of Moses at a fundamental level, destroying the community life. For this, they can expect all their land to offer a reverse yield of roughly one for ten, and their mansions will stand empty.
Second, the life of dissipation as a result of inordinate wealth. Since wine was a major product and recommended by God, it's hardly the drinking which is sinful, but the manner and context. These people don't work as God had intended for all men, but party. Not necessarily sweaty work, but no work at all. They just party all day and night. Scholars, singers, bookkeepers, managers, as well as farmers and herders all work, doing something which engages their time and produces a benefit to the community. Isaiah points out they do none of these things. They bless no one by how they pass their time, and this is not how God planned human life to be.
Isaiah then takes a moment to describe the result of this party-hearty lifestyle. The whole nation is enslaved to such frivolous entertainment, and they are pitifully ignorant of truth. The few who are wise and honorable starve to death, and the core of leaders and teachers which give a nation character and renown are all gone. These partiers are prancing away into death. Whatever else happens, this horror will end if God has to crush it Himself. He would rather see the land of Canaan managed under foreign government than to see any more of this.
Third, the nation's social leaders mock the old ways. They have harnessed themselves to evil as if it were some new fashion. They dare to suggest if God cares He can defend Himself. The implication is God isn't keeping up with the times, and needs to offer a fresh revelation, and is not diligent enough to enforce His commands. If what they are doing is wrong, what's taking Him so long to react? They suggest His patience is lack of interest.
Fourth, these same leaders have seized upon some new fashion in human science. It became their excuse for turning things upside down, for rejecting God's standards. Such intelligent folks, they were sure. Connected with this was a fifth: Human standards of wisdom dreamed up by fallen human intelligence. They had complete disregard for revealed truth, and were enamored with their own mental gymnastics.
Sixth, standards of justice and just good plain sense had disappeared. The social leaders were so proud of their skills with wine and cuisine, but had no clue about standing up for what is right. Thus, justice was for sale. Evil men bought their way out of trouble, while good men went to prison.
Having strayed so far away from God's path for them, they left themselves wide open. Only in obedience could they expect peace and safety. Instead, they had chosen self and sin as their gods. Thus, it was a natural result, Creation itself would turn against them. What was rotten would not persist. But there's more, for they have simply gone too far.
The sentence against them was a massive invasion. God would set forth in invitation to some far distant rulers. Further, the protection and prosperity He wanted to give Israel would be reserved for her enemies. These advancing armies would be swift as the wind, and would not tire at all on their long march. They would arrive as sharp, clean and battle ready as they left -- even stronger, if possible. Nothing would wear out, echoing the blessings of the Exodus, which Israel reaped even during their 40 Years of Wandering.
Rather than the roaring of toothless old lions driving the prey to the young lions, these would be the young lions, seizing their prey without warning. In the middle of the battle, they would remain comfortable and safe, as God would ensure their victory. Israel would find themselves driven to the sea, with no escape, and the weather itself would be against them.
Note these are largely symbolic, but represented the very real earthly blessings Israel could have had against her enemies. All it took was simple adherence, a rather easy level of acceptance, of what God required of Israel. Other nations did not have this advantage, but we note Isaiah says Israel simply threw it all away.