Did Constantine Change the Sabbath?

In AD 321 Constantine decreed: "On the venerable day of the Sun let the magistrates and people residing in cities rest, and let all workshops be closed." This was a civil law about rest from labor, framed in language familiar to both Christians and sun-worshiping pagans. It did not claim to transfer the Sabbath; it gave Sunday legal standing in Roman public life for the first time.

Sunday observance appears in some second-century Christian writings, grew through the third century, received civil backing from Constantine, and ecclesiastical reinforcement at councils such as Laodicea (c. AD 364), which told Christians to rest on the Lord's day and not Judaize by resting on the Sabbath. The shift from the seventh day to the first took centuries and was complete only in the medieval church.

This matters because the prophecy matches a process, not an edict: the little horn would "think to change times and laws" (Daniel 7:25) — an attempted change, worked out over time through religious authority allied with civil power.

Acts 20:7 (a night meeting at Troas) and 1 Corinthians 16:2 (setting aside money at home) are the standard texts cited for first-century Sunday observance; neither calls Sunday the Sabbath or a day of worship, and both have their own context. Jesus called Himself "Lord also of the sabbath" (Mark 2:28) — of the seventh-day Sabbath He had kept. The disciples kept the Sabbath after the crucifixion "according to the commandment" (Luke 23:56), and Paul preached to Gentiles on the Sabbath in Acts 13:42–44.