Fulfilling the Sabbath
So then, there remains a Sabbath rest for the people of God, for whoever has entered God's rest has also rested from his works as God did from his. Let us therefore strive to enter that rest, so that no one may fall by the same sort of disobedience.
Sabbath-keeping is an issue that has long divided Christians. Some have argued that we need not regard one day of the week differently than any other. The matter is complex, but essentially, many believers argue that we are not obligated to keep a new covenant Sabbath because Christ has fulfilled the law (Matt. 5:17).
However, we must understand that the fulfillment of the law occurs in the entirety of our Savior's mission, which has not yet been finished. Certainly, He completed His work of atonement on the cross (John 19:30; Rom. 3:21–26), but the work of bringing all things under His feet continues (1 Cor. 15:20–28). Until this work is finished in the consummation of the new heaven and new earth, unfulfilled elements of the law remain in force. For example, we no longer offer animal sacrifices because they were fulfilled on Calvary (Heb. 9:1–10:18), but we still need to hear God's moral law, work hard to observe it, and repent when we break it because Jesus has not yet finished writing His law on our hearts or removing the presence of sin. That will not happen until our glorification, when the moral law will be a part of our very nature and the thought of breaking it will never even cross our minds (Rom. 8:18–30; Phil. 3:20–21; 1 John 3:2). The new covenant is here, and yet it is not here in all its fullness, as Christ has not yet consummated His kingdom. The old covenant is "becoming obsolete"—select aspects of it have not fallen away entirely (Heb. 8).
Today's passage says a Sabbath remains for God's people. Jesus has not yet entirely fulfilled the Sabbath, for some of His sheep have not yet heard the gospel and entered their eternal rest. We begin in this life the eternal Sabbath, worshipping and resting on the Lord's Day as a testimony to our eternal rest (Heidelberg Catechism, Q&A 103).
Reformed theologians have differed over how Christians are to observe the Lord's Day. All agree that it should be a day of worship, rest, and doing mercy. Also, everyone concurs that work required to maintain life is permitted (Matt. 12:9–14). Disagreements concern whether "worldly" recreation is permitted. In keeping with what has been often regarded as the Continental view of the Sabbath, we believe that recreation is permitted as part of resting on the Lord's Day. But as many good and godly Christians have differed over this issue, Sabbath observance is not something that should divide us.
Coram Deo
The fact that people have disagreed over Lord’s Day observance and that it should not be an issue that divides Christians is not to say that the matter is unimportant. Instead, it is to recognize that there is a degree of ambiguity on this matter that we don’t find with issues such as the doctrine of the Trinity or the deity of Christ. Whatever view of the Sabbath we hold, we should endeavor to make sure it can always be reformed by Scripture when necessary.