What do you think this passage means?

I think Madison meant that, assuming there is a god at all, such a being's intent could not possibly be understood and interpreted through something as crude as the human language. This is doubly true when the message must be re-interpreted through several different languages, as is the case in the Bible. It's a strong argument against literal interpretations of the Bible.

It's the problem of language inherent in any sort of human communication. I certainly do agree.

Then again, I'm of the opinion that the divine, whatever it is, manifests itself to each person in the way that he or she can best understand. To some, Christianity makes no sense, and if there is a god, is unable to communicate through Christianity with that person (just as an example. Fill in the blank with whatever religion or lack thereof).

Sounds like a good argument against Sola Scriptura and argument for a Church.