I just finished listening to a very well done teaching series on the Lord’s Day. Dr. Matthew McMahon does a very good job of showing from the scriptures of why we worship on the first day of the week. He answers the question of whether the fourth commandment is part of the moral law, or simply part of the ceremonial law that was done away with at the resurrection of Christ.
Dr. McMahon is a paedo-baptist Presbyterian. Although I disagree with him on infant baptism, I have found his handling of the Word of God to be quite good. To hear a very good teaching on this subject, visit his website at http://www.apuritansmind.com/CD/DominicumServastiAudioCD.htm
One point that he mentioned that I had never considered before is that in the creation ordinance of a Sabbath day rest, we are never told that the day is actually Saturday (or the ancient name for that day). The Israelites recognized this day as their Sabbath when the Lord brought them out of Egypt by His mighty hand. The next day was the Sabbath day, and it was kept holy to the Lord.
For the Christian, Christ has brought us liberty from the bondage of sin. Therefore we worship Him on the first day of the week, the Lord’s Day. It is the Christian Sabbath, the keeping holy of this one day out of seven unto the Lord.
Check out McMahon’s series. I enjoyed quite a bit.