One of the most striking things about the rise of Christianity within its Jewish origins is the fact that the Sabbath moved from the 7th day (Saturday) to the 1st day (Sunday). We know why this happened – Jesus was resurrected on the 1st day of the week, but sometimes we wonder how this happened.
In conversation some time ago, Becca told me that she thought there was mention of this switch in the New Testament, but couldn’t remember where. I searched for a while, but found nothing. But just this morning, my lectionary took me into Acts 20, and behold…
On the first day of the week we came together to break bread. Paul spoke to the people and, because he intended to leave the next day, kept on talking until midnight.
No, it’s not a command, and no, Acts is not necessarily a case study in ‘what church ought to look like,’ but at least we do have a description of what was going on. And by this point (57 AD), Christians were already gravitating toward Sunday corporate worship rather than the former Saturday corporate worship.
Both a theological and a sociological lesson can be gleaned from this switch: theologically it sheds a new light on the definition and purpose of the Sabbath. In Jewish culture in Jesus’ time, the Sabbath was this inviolable thing which many people treated legalistically. Many of Jesus’ parables and teachings addressed this misuse of the Sabbath, and can be summed up in his words “man was not made for the Sabbath, but the Sabbath for man.” Theologically, this brought us back to the understanding that the Sabbath is not something that we serve as a master or law over us, but something that we need for our own benefit… the why is more important than the how. Sociologically it highlights the serious cultural power of the Christian movement – overturning such a fundamental Jewish identity marker makes it clear that Christianity was not just some little cult rising up, but a very significant thing indeed!
Leorningcnihtes boc 
The verse in Acts alludes that the Sabbath is not only about rest (genesis 2:2) from work, but its about community :). Of course, the Sabbath is not a rest from doing good deeds. Which makes me wonder, should there be a separate Sabbath day for those who work in ministry? While their job involves good deeds and community, it is also work.
I can’t help but be a little picky and say that the Sabbath is about worship, and community derives from that secondarily. My argument for that is in the middle section of my previous post about Advent & Christmas.
You’re absolutely right about ministers needing a Sabbath beyond Sunday, though, who are essentially working at church worship. Most clergy I know take Monday off as their rest-sabbath.
Additional comments from Facebook feedback (c/o Bob Craig & Isaac Demme) have provided more nuance into the role of Sabbath & Sunday in Early Christian life:
Ignatius of Antioch comments on this matter in his Epistle to the Magnesians, chapters 8 & 9. He exhorts his hearers: “For if ever unto this day we live after the manner of Judaism, we avow that we have not received grace:…”
“And after the observance of the Sabbath, let every friend of Christ keep the Lord’s Day as a festival, the resurrection-day, the queen and chief of all the days [of the week]. Looking forward to this, the prophet declared, ‘To the end, for the eighth day,’…”
Remember to distinguish the day of Christian assembly from the chief feast of the week from the day of rest and mediation. As far as I can tell, Ignatius was arguing that Sunday should be the chief feast day, and probably the day of assembly, but he still held that the seventh day was the Sabbath, and the day of meditation on the Law (although he downplays the rest element).
Likewise, it seems clear from many sources (and is consistent with Acts 20) that Christians in the 1st century were assembling for worship and Eucharist on the first day of the week, but observing a day of rest (and synagogue attendance in many locales) on the seventh day. I haven’t found any source earlier than the fourth century (although there may well be one I am not aware of) that treats the Lord’s Day and the Sabbath as overlapping feasts — most early sources seem to treat them as distinct and different concepts, even referring to the Lord’s Day (as Ignatius does) as the “eighth day” of the week.