What's Going on in Judaism?

During this time, the jews go from being an independent nation to being a kind of sub population within the larger, larger population the roman empire. And so what judaism finds themself in is, how do we survive in this world and not lose our identity? Sa am: Can you fill us in on the situation that the jewish people find themselves in, and whythey may have become so, so concerned about sabbath worship and maintaining it?