The sanctity of the Sabbath was instituted at Creation. After His creative work of six days, God rested on the seventh day and hallowed it. By hallowing it, God set the seventh day apart. He consecrated it as holy. Proper observance of the Sabbath was one of the Ten Commandments given at Mount Sinai. It is important to remember that its institution was an integral part of the creation covenant. In the Old Testament, violation of the Sabbath was a capital offense.
The word Sabbath means "seventh." That is why some insist that Saturday is the only proper day to celebrate the Sabbath, and that it is illegitimate to observe it on Sunday. However, historic Christianity has always observed Sunday as the Sabbath because in the New Testament it is "the Lord's day," the day of Christ's resurrection. The principle of Sabbath, one in seven, remains intact. The weekly Sabbath has been in perpetual effect since Creation and was observed by the apostles.
Questions of proper Sabbath observance continue to be debated among theologians. Most agree that the Sabbath includes a mandate to rest from all but necessary commerce or labor. The Sabbath is also a time for corporate worship and special attention to the study of God's Word. It is a special time of rejoicing in Christ's resurrection and in the hope of our Sabbath rest in heaven.
Disagreement centers on the role of recreation and works of mercy. Some regard recreation as a worldly violation of the Sabbath, while others insist it is an important part of rest and refreshment. The Bible nowhere explicitly promotes or prohibits recreation on the Sabbath, though the meaning of pleasure in Isaiah 58:13 may suggest that it is prohibited.
A less strident debate focuses on the issue of works of mercy. Many appeal to Jesus' example of special ministry on the Sabbath Day as an implicit command for Christians to be actively engaged in works of mercy on the Sabbath, such as visiting the sick. Others contend that Jesus' example proves that it is lawful and good to be so engaged, but that what is allowed is not necessarily required. (That such works of mercy are not limited to the Sabbath is clear.)