Christians are not bound by the ceremonial laws of the old covenant. We are obliged to live by the moral principles. For example the ten commandments. We Christians are to live in gratitude and freedom and our lives should be governed by the Holy Spirit. But if one thinks that Christ was just a liberal and the real son of Joseph, then this discussion in my opinion is totally pointless. It's just arguing for the sake of arguing. I find that the unbelievers want proof that Christ is God the Son. I can't oblige. I have faith, and that doesn't require the scientific evidence that the atheists demand.
Are you calling me an atheist?
You seem to be saying that you can pick and choose which laws you abide by. It seems that you decide which of the OT laws are from God, and which are not? If the Bible is 'inspired' by God then surely all the laws He sees fit to include are from Him, otherwise all is up for grabs?