This is an appendix to Dr. Gary North's book, the Sinai Strategy. It can be found and downloaded for free from the "free books" section of www.garynorth.com.
Every time I read this, I get a bit upset at some of his interpretations. However, he raises questions that EVERYONE who considers themselves a sabbatarian has to ask, and have never been adequately answered so far. This appendix is a very good as a standalone essay. I recommend all theonomists, Torah keepers, and really, all other Christians who want to honor God's commandment to keep the Sabbath, read this and soberly reflect on how we've misapplied God's Word in this area.