'Thing' in the Bible

It is a very small thing to me that I should be examined by you or by any human court. In fact, I don't even evaluate myself.

and those who mourn as though they did not mourn, and those who rejoice as though they were not rejoicing, and those who buy as though they did not own a thing,

I am not saying this on human authority, am I? The Law says the same thing, doesn't it?