Why do some people think we changed the Sabbath from Saturday to Sunday?

The notion that Christians changed the Sabbath from Saturday to Sunday stems from misunderstanding the purpose and significance of these days. The Sabbath was the seventh day of the week, instituted within the Old Covenant for Israel as a sign of their relationship with God after the Exodus. When Christ came, He fulfilled the Sabbath's requirement, and the early church began to celebrate the Lord's Day on Sunday—the first day of the week—commemorating His resurrection. This shift does not equate to a change of a day but rather reflects a transition from the old covenant sign to the new reality of Christ, who is our true rest. This distinction is crucial for understanding our call to worship in the light of the new covenant.