פרק ב is all about G-d's anger and the destruction that he puts upon ירושלים. In פסוק ח it says, "He stretched out a line," when talking about all the destruction that was happening. When else would you see the phrase "stretching out a line" if not referring to measuring. When you measure, we use a ruler that guides us to find the exact length of another object. Why would this phrase be said here in a writing that is describing complete destruction? G-d doesn't seem to be having any mercy here. Not even for the innocent babies. He destroys everything. Why does G-d need a "measuring stick" or a guidance to destroy the city of ירושלים? 

ירושלים makes G-d seem like an enemy and a betrayer. But this is not the case. G-d wants us to succeed. G-d doesn't get enjoyment from destroying us. He wants us to be better people, so he has to give us punishment to learn our lesson. This way we won't make the same mistake twice. G-d knows he cannot be merciful in this situation, so he needs guidance to keep him from straying off course and being merciful. 

Sometimes there a situations when you don't want to do something, but you know it will benefit better in the end. You always need something to guide you in the right direction to stay on your task.