Does Acts 21 Confirm Sabbath Keeping for Believers?

I have to confess I have a problem with James.1 No, not the book. I don’t have Martin Luther’s difficulty.2 But I do have a problem with James’ attitude and actions towards Paul in Acts 21, when Paul returned to Jerusalem after his work among the Gentiles. It was all to do with the law, the law of Moses, in connection with converted Jews and Gentiles. And the way James spoke to Paul, and dealt with him, does leave me in a bit of a quandary.