The weekly memorial of the new creation and our deliverance from sin. Only Jews were given the Sabbath, not Gentiles who have never been slaves in Egypt or delivered out of physical slavery by the power of God.
Christians observe a new day in remembrance of their new creation and new redemption.
Our new redemption is a greater redemption than freedom from physical slavery. The new redemption of the Christian is the redemption found in the blood of Christ. Those under the Law had been redeemed from Egypt, but they needed a greater redemption. Six days you shall labor and do all your work, but the seventh day is the Sabbath of the Lord your God. For in six days the Lord made the heavens and the earth, the sea, and all that is in them, and rested the seventh day.