The fourth commandment is not only the longest of the Ten Commandments, but it also begins differently from the other nine. The other nine start with "You shall" or "You shall not." (The first commandment may be an exception, but many consider its opening sentence—Exodus 20:2—to be a preamble to the whole Decalogue. Thus, the first would also begin with "You shall.") The fourth commandment, though, stands out by beginning, "Remember the Sabbath day, to keep it holy" (Exodus 20:8).

God could have made it conform to all the others, but He did not, making His departure from the norm significant. He could have said, "You shall keep the Sabbath day holy" or "You shall not work on My Sabbath day." But, no, He charges His people to remember the Sabbath day. Something about remembering is vital to understand what the Sabbath day is all about.

The Hebrew word in question is zākar (Strong's #2142), a primitive root that means "to remember, think of, mention." It can also carry the sense of "meditate upon," "pay attention to," "proclaim," and "commemorate," among others. Like other Hebrew terms (for instance, šāmaʿ, "to hear," which implies "to obey"), it blends a mental activity (remembering, thinking about) with an external one (in this case, observing the Sabbath). It is not enough to remember; remembrance must flow into observing the day as holy.

English verbs, including "remember," sometimes possess this internal/external property too. The intent behind the battle cry, "Remember the Alamo!" was not just to reminisce over the heroism of the Texans who defended it but to encourage bravery and martial spirit to avenge those who had died there. When an English bartender told his patrons, "Mind your ps and qs," he wanted them not just to recall how many pints and quarts they had drunk but also to pay up before they left the pub. When a teacher tells her students, "Remember the test tomorrow," she is not just reminding them of the exam but encouraging them to study for it.

God wants us to remember His Sabbath and respond by keeping it holy. The command implies that if we remember the Sabbath day properly—that is, with godly understanding—then our only appropriate response is to keep it holy. A thorough, accurate conception of God's intent in commanding us to hallow the seventh day will leave us no option but to observe it with the utmost reverence. Why?

The Principle of First Mention provides enlightenment on this point. Zākar appears first in Scripture in Genesis 8:1 during the Flood: "Then God remembered Noah, and every living thing, and all the animals that were with him in the ark. And God made a wind to pass over the earth, and the waters subsided." We recognize at once that the internal/external property of the Hebrew verb is in play. God remembers them and acts by sending a wind to dry up the water covering the earth.

What is not so obvious is why God, amid all His re-creative activity after destroying the earth in the Flood, even remembered Noah and the other still-living creatures on the ark. The ultimate reason for God's remembrance is that He had made a promise in the form of a covenant with Noah about this very thing in Genesis 6:17-19:

And behold, I Myself am bringing floodwaters on the earth, to destroy from under heaven all flesh in which is the breath of life; everything that is on the earth shall die. But I will establish My covenant with you; and you shall go into the ark—you, your sons, your wife, and your sons' wives with you. And of every living thing of all flesh you shall bring two of every sort into the ark, to keep them alive with you; they shall be male and female.

God's remembrance of Noah—and eventually bringing the ark to rest on the mountains of Ararat—was His response to the agreement He had made with Noah. He remembered the terms of their covenant and acted appropriately, ensuring their survival through the Flood.

In the same narrative, the next use of zākar verifies this implication of the word: ". . . and I will remember My [rainbow] covenant which is between Me and you and every living creature of all flesh; the waters shall never again become a flood to destroy all flesh" (Genesis 9:15). We see it again in Genesis 19:29, where God remembers His covenant with Abraham and so saves Lot from the destruction of Sodom. In Exodus 6:5-6, He remembers the covenant and promises to bring Israel out of their Egyptian slavery. When Jerusalem was about to fall, Jeremiah cried to God, "Remember, do not break Your covenant with us" (Jeremiah 14:21).

These instances of zākar encourage us to see "Remember the Sabbath day" in Exodus 20:8 in a covenantal light. Since the Ten Commandments stand at the beginning of the Old Covenant, we would be foolish to ignore it. The people had already promised, "All that the LORD has spoken we will do" (Exodus 19:8), so God reminds them in the fourth commandment that they have a weekly observance to perform as a solemn duty under the covenant. If they wished to receive all the promised blessings, they had to keep the Sabbath holy.

God reinforces the importance of the Sabbath as a covenantal responsibility in Exodus 31:12-17. Notice verse 16: "Therefore the children of Israel shall keep the Sabbath, to observe the Sabbath throughout their generations as a perpetual covenant." The Sabbath itself is a separate covenant within the covenant! As in the Ten Commandments itself, God makes a particular point of distinguishing Sabbath-keeping from other covenant responsibilities.

What is so special about keeping the Sabbath holy? The answer appears in the same passage: "Surely My Sabbaths you shall keep, for it is a sign between Me and you throughout your generations, that you may know that I am the LORD who sanctifies you" (Exodus 31:13; emphasis ours). The upshot of keeping the Sabbath under the covenant is that doing so ensures that we remain holy or sanctified. The Sabbath not only acts as a sign of who God's people are, setting them apart from other peoples who do not keep His laws, but it is also the day in which God's people meet with Him in holy convocation to learn and grow in holiness and righteousness, which is the ongoing process of sanctification. If we fail to meet with Him on His day, we will eventually lose our understanding of what is godly and slip back into the world from which He called us.

As God's chosen people, we must remember that observing the Sabbath day is our solemn responsibility under the New Covenant we have made with Him. Understanding its importance to us and our great hope to attain the Kingdom of God, we can do nothing but keep it holy.