Consider where this covenant appears. It is in the book of Exodus, but after chapter 20, where God gives the commandments. From this we see that God proposes a special covenant, which He places in the midst of all of the instructions for building the Tabernacle. It means that, even though these people were employed to construct such an important edifice for the worship of God, they were not to desecrate the Sabbath by working on it. Even the construction of the Tabernacle had to take second place to the keeping of the Sabbath.
The Sabbath is a sign. It is not a mark. Bible usage shows that a sign is voluntarily accepted, whereas a mark is put on against a person's will. The Sabbath is a special sign. It is a special covenant between God and His people. Who are His people?
A sign can identify an occupation. One might read, "Joe Smith, Dentist"—or plumber or electrician. A sign can also give purpose for a thing; it tells us why something is being used or done in the way that it is. A sign can give directions: "This way to River City."
A sign can also bring people together with shared interests and common purposes. Some fraternal organizations have special signs that they pass to one another to identify what lodge, or organization, it is that they belong to. A sign can unify; it can bring people together. A sign can be a pledge of mutual fidelity and commitment. Signs are used by organizations to designate membership. People wear a little badge on their lapel that says that they belong to such-and-such organization, and by it members recognize one another.
This is part of the way that the Sabbath is also used. The Sabbath serves as an external and visible bond that unites and sanctifies us [sets us apart] from everyone else. Here in the United States and Canada, almost everybody else who is religious keeps Sunday or nothing. If a person keeps the Sabbath, he is being cut away from, separated from, sanctified by the very fact that he is keeping it. Though these people do not realize it yet, it becomes a sign to them that he is in the process of being sanctified. We ought to be very much aware of this sign because we are keeping it.
Everybody who has ever kept both Sunday and Saturday knows this: Sunday sets almost no one apart because everybody who is "religious" is already doing it. Big deal! What is so different about that? They are only sanctified from the people who keep no day at all. For those who are "religious," it does not sanctify them because the Baptists are keeping the day, and the Catholics are keeping the day, as well as the Mormons, the Pentecostals, the Church of Christ, the Disciples of Christ, and the Congregationalists. All those people are keeping Sunday, and it is not separating, or sanctifying, anybody.
But once a person begins to keep the Sabbath, it immediately begins to sanctify him, to separate him from everyone else. God has a purpose that He is working out. He has made a tremendous investment in the Creation and in the death of His Son. The Sabbath is a means by which He protects His investment.
If the only reason He created the Sabbath was because we need rest, then any old time would do. Ultimately, how and why one keeps the Sabbath are the real sign. Other religious groups "keep" the Sabbath, but are they keeping it as God desires? It is how and why we keep it that makes us different—they do the sanctifying. "Sanctify them through Your truth," Jesus says in John 17:17. God's Word is truth. If people accept it and use it, they will be using the Sabbath for different purposes than others are.
God created the Sabbath to educate His people in His way. It prepares them for their witness. Suppose that a basketball coach says to his players, "Come to the gym and meet with me at such-and-such a time." But some of the players decide that they will go to a different gym, at a different time, and with a different coach. Players on a team begin to take on the qualities and the philosophy of their coach. Anybody who is familiar with athletics understands this. Those who are intimately involved in athletics say that they can always tell whether a certain player has been coached by a certain coach, say John Wooden or John Thompson. What has happened is the player has taken on the sign of the coach, and it has sanctified him from other players who are not coached by that particular coach.
The same principle is at work with God and us. He is our Coach. He has made an appointment with us to meet at a certain place, at a certain time. And if we choose not to go to where He is going to be, then we are not going to begin to take on the image of our Coach. The Sabbath was created because it both enhances and protects our relationship with God. And it provides the witness—to God, to the individual, and to the world—of who is keeping it. This is how it becomes the sign. It provides a witness.
The Sabbath exists to keep us in a proper frame of mind and to provide us with the right material to negotiate the way to God's Kingdom. We live in a grubby, grasping material world. Every day has a built-in bias towards material things, and it is very difficult to keep our minds focused on things that are spiritual. But the Sabbath, if a person is keeping it as God desires, will almost put a person into a spiritual mode, point him toward God, and force him to acknowledge Him as Creator.
The Sabbath presents us with the opportunity to consider the whys of life, to get our head on straight with the right orientation so that we can properly use the other six days. The Sabbath is the kernel, the nucleus, from which the proper worship—our response to God—grows.
Existentialist philosophers tell us that life is absurd, that all of life is nothing but a prelude to death. But keeping the Sabbath is a celebration of life! It tells us that God's creative process is continuing, that He is creating us in His spiritual image so that we might live with Him forever. For the great God, the Sabbath is a day of creation. The Sabbath ensures us that life is not absurd, but rather, it is a prelude to life on an infinitely higher and greater level. The more we become like Him, the more sanctified we are from the world. It is in experiencing the refreshing elevation of the mind that we get a tiny foretaste of what is to come.