But now we have been released from the Law, having died to that by which we were bound, so that we serve in newness of the Spirit and not in oldness of the letter.
I also work on the Sabbath. (Sunday; the Sabbath is different for different groups) It used to bother me. But I do it because its the only day I can contribute to the financial needs of my family. First, there's love covers over a multitude of sins - but I don't think its a sin. Second, even Jesus said that it IS good to do good on the Sabbath.
The new law is love. That will mean different things to different people; so we are expected to think and question and not just obey. This is what I think, anyway.