First-day and Seventh-day Christian Sabbath keepers often debate whether the fourth century Roman emperor Constantine chose the right day when he made Sunday rather than Saturday the weekly day of rest for the entire empire. This debate, which has continued for centuries, has produced an impressive amount of excellent scholarship about how Christians gradually eclipsed the Jewish Sabbath with the Christian Lord's Day.
The best thing that can be said about this slow and uneven transition is that it expressed the overwhelming importance for Christians of the resurrection of Jesus on the first day of the week. The worst is that it articulated a growing anti-Judaism among Christians which would intensify throughout the Middle Ages and well into the twentieth century when it fully manifest itself in horrors like the Holocaust. An objective examination of the evidence suggests that it was both but that the degree to which it was one or the other varied according to period, place and people.
Too often those on both sides of this debate forget that the most important issue is not whether Constantine rightly endorsed either Saturday or Sunday but that he endorsed, with all the coercive power of the Roman Empire, either day, or any other one for that matter, in the first place. His fateful mistake, which eventually caused much needless suffering, was not that he endorsed Sunday but that he endorsed Sunday. Using the coercive power of government to make Christianity, or any other religion, the official one is the essence of the Constantinianism to which many today rightly reject.
Those of us who are Christian can do a better job of focusing on the most important questions. In this context, it is not whether we are First-day or Seventh-day Sabbath Keepers. It is whether or not we are Constantinians.