Israel is in exile, looking for some answer as to what happened. The prophet Isaiah speaks into this situation and reminding them that the Lord has allowed this to happened to them because (AGAIN) they disobeyed the Lord's commands, and continued to reject their relationship with God.
Some of us have to learn lessons the hard way. The Bible speaks of our relationship with God like children and parent. God being the benevolent parent and we God's children. So it goes, sometimes children misbehave and disobey.
As a parent, on more than one occasion I have found myself allowing my children to do things I know that might hurt them (not severely mind you) so that they might learn from them. When they inevitably do hurt themselves, I might even say "that'll learn ya."
Israel is in a learning process here because they took advantage of God's promises, thinking God will always protect them even when they refuse to do as God commands them. God allows the exile to happen upon God's children because the current system of relationship is not working. God commands and promises covenant relationship and the people break that covenant and reject God, hoping God will do something for them anyway.
Isaiah prophesies judgment upon Israel, but also promises a svior to come and change the way we know God. God will come down from heaven and dwell among us....so that we can be in intimate relationship.
Lord, benevolent God, loving parent, guide us as your children so that we may learn to follow you and your commands more clearly.