Can u give me an explanation why never judge a man until you've walked two moons in his moccasins

I believe this is the same concept of " never judge a book by it's cover" simply meaning you should never judge someone because of their outward appearance or actions, you don't know what is going on in there lives.

And also saying "try walking in my shoes" is another phrase comparing with dont judge a man by its cover unless you lived his life and completely knew him