The Law I'm talking about is the one embodied in the Ten Commandments, which Jesus said can be boiled down to love of God and love of neighbor, which He spelled out in the Sermon on the Mount, but which are also spelled out particularly in the Pentateuch but in fact throughout the Bible.
Then I take it that we are required to observe the sabbath.
This is a law to be understood and obeyed in spirit and not in legalistic obsessional letter, as Jesus said. It is moral principles to be grasped and applied to different situations. Many laws in the OT are too hard to translate into modern terms, but sometimes a principle can be extracted that applies even if the specifics don't.
I guess we don't have to observe the sabbath after all. Moral relativism is in. Strict constructionism applies only to the US Constitution, and not to the Bible.
I guess it must all be a matter of personal convenience. If strict constructionism for the constitution supports the way we want to do things, go that way. If strict constructionism on the Bible is inconvenient, we can be more flexible.