Compare a XML Response with a File

I am looking to compare the response from a message with a saved XML response on my machine and want to compare the two to check that they are indeed identical.

I have been reading through the documentation and was looking to create an assertion script once the response was returned.  However, I have not found a good way yet.  I am new to this so I know that I am missing some key pieces and was wondering if someone could point me in the right direction.