Daniel 9:14 (ESV)

14 Therefore the LORD has kept ready the calamity and has brought it upon us, for the LORD our God is righteous in all the works that he has done, and we have not obeyed his voice.

The Lord is not some weak and impotent God. Nor is he a God who is asleep. He does what he promises he will do. He is really awake. He sees what his people is doing, and therefore he comes with his judgment. That is his righteous punishment, even down to the destruction of Jerusalem and the temple. The Lord is just. He will never come up with an unfair or unjust punishment. The people should blame themselves.