When I hear most Christians talk about the ancient Jewish religion, I usually hear something along the lines of, "Those crazy Jews...they thought their works could make them righteous." Now, for the moment let's choose to ignore the racial prejudices behind such a sentiment. Let's also ignore the fact that such a sentiment is imposing a misunderstanding of Martin Luther over ancient Judaism. For now, let's just look at how ancient Judaism actually functioned. The Jews didn't offer sacrifices and follow the Law because it made them righteous. God brought them into a covenant with himself, provided them with formative instruction, and Jewish religious practice flowed out of that. Saying the Jews believed following Torah would bring them into or keep them in a relationship with God is like putting the cart before the horse. It's not a matter of works leading to righteousness. It's a matter of relationship leading to good works. A good Jew doesn't believe his or her works will make him or her worthy. It is the fact that God called them out of Egypt that makes the Jews want to respond with obedience. Christians believe that we should be sexually pure. Why...because we think sexual purity will bring us into a relationship with God? No, because God loved us while we were still sinners. The activity is a response to God, not a bribe to God. That, at least, has not changed from Old Testament to New Testament.