What does the Bible say about the significance of the first day of the week?

The first day of the week, also known as Sunday, is significant in Christian theology because it commemorates the resurrection of Jesus Christ. John 20:1 captures this moment, emphasizing that Mary Magdalene visited the tomb early on this day, signifying a new beginning for believers. The resurrection of Christ not only validates His identity as the Son of God (Romans 1:4) but also establishes Sunday as the day of corporate worship for Christians, honoring the completion of redemption.