On the seventh day God finished his work that he had done, and he rested on the seventh day from all his work that he had done. So God blessed the seventh day and made it holy, because on it God rested from all his work that he had done in creation. (Genesis 2:2-3)
The seventh day is the very first thing to be hallowed in Scripture, to acquire that special status that properly belongs to God alone. In this way Genesis emphasizes the sacredness of the sabbath. – Bruce Waltke 
After six days of creation, God looks upon the works of his hands and pronounces it “very good” (Gen 1:31). But it is not until the seventh day that God calls something, “holy,” the day of rest that he interjects into the time and space of creation. The day of rest receives the attribution of holiness, which is the very essence of God’s character. The two short verses of Genesis 2:2-3 emphasize three times that God rested.
Today, many people think of rest as something they have to do so that they can work. Given the choice, some people would prefer bodies that did not need rest. In modern society, rest is often seen as the opposite of productivity. Rest is a functional necessity, serving the higher end of work, devoid of higher meaning or significance. Is this view of rest and work biblically accurate?
In Genesis 2 God both works and rests. God, in his omnipotence, clearly does not need to rest for reasons of physical tiredness or exhaustion. He does not need to rest so that he can become more productive, given that he has already created everything. So clearly there is something more to rest than maintaining energy for the production line.
It is also interesting that the first thing in all of creation that is made holy is not a person or even an object, rather it is a day. What then is the significance of rest for God, and why does he make this day holy? Genesis 2 does not say why God makes the seventh day holy, merely that he does make it holy. So it helps to turn to the concept of sabbath as it is developed throughout the Bible. Surprisingly, the term sabbath does not appear again until Exodus 16:23-29, when Israel is wandering in the wilderness after being delivered from Egypt. The next significant mention of sabbath occurs in the giving of the Ten Commandments in Exodus 20:8-11. The fourth commandment to remember the sabbath and to keep it holy is grounded upon God’s pattern of working six days and resting on the seventh, making an explicit link between creation and sabbath observance, “For in six days the Lord made heaven and earth, the sea, and all that is in them, but rested the seventh day.” (Exodus 20:11). Israel is commanded to rest because God rests in creation.
It is important to note that the sanctity of rest in no way undervalues the importance or dignity of work. Rather, these opening chapters of Genesis establish a pattern of work and rest; to do one without the other is a deviation from God’s created order. In fact, the fourth commandment combines both a command to work and to rest: “Six days you shall labor and do all your work.” God affirms the goodness of work and the sacredness of rest, with the two beautifully woven together. The fourth commandment as given in Deuteronomy supports the rhythm of work and rest with a different argument—because of God’s deliverance of his people out of Egypt. “Remember that you were a slave in the land of Egypt, and the Lord your God brought you out from there with a mighty hand and an outstretched arm; therefore the Lord your God commanded you to keep the Sabbath day.” (Deuteronomy 5:13-15) People should work and rest as God instructs because of his model in creation and his model in redemption.
Exodus 31:16-17 provides even deeper insights. “Therefore the Israelites shall keep the sabbath, observing the sabbath throughout their generations, as a perpetual covenant. It is a sign forever between me and the people of Israel that in six days the Lord made heaven and earth, and on the seventh day he rested, and was refreshed.” Two important discoveries come from this passage. First, the sabbath functions as a sign, pointing to the “covenant” between God and Israel. This covenant embodies the privileged relationship that Israel enjoys with God, which begins with the patriarch Abraham. Old Testament scholar John Durham writes in his commentary, “The reason the sabbath is to be kept is that Yahweh has commanded it as a sign of the covenant in perpetuity between himself and Israel, the covenant by which Israel has made a response to the gift of Yahweh’s Presence.” In other words, keeping sabbath is a living out of the special relationship God’s people enjoy with God. Second, the sabbath is a day when God himself is “refreshed” and he wants his people to experience that same refreshment. Thus the sabbath enacts God’s desire to be in intimate relationship with his people. God offers his people weekly refreshment through communion with him and with his creation.
Further evidence of this relational aspect of the Sabbath emerges in Ezekiel 20:12, “I gave them my sabbaths, as a sign between me and them, so that they might know that I the Lord sanctify them.” According to this verse, God gives Israel “his sabbaths” (the refreshment that belongs to him, as a relational sign between God and his people) so that they might know who he is as well as know the sanctifying effects of relating with him. Old Testament scholar Bruce Waltke corroborates this relational emphasis: “[T]he sabbath is the sign that Creator has set Israel apart for a special covenantal relationship with him.” The sign is not arbitrary, like a tattoo or a secret gesture. Instead, the sign of sabbath is real participation with God in the delight of resting in God’s own creation. God chooses not to be distant from his creation. Rather, God chooses to intimately commune with his people and with his creation through their participation in his sabbath rest.
The New Testament extends both the directive to enter into God’s rest and the possibility of doing so. Hebrews chapter four encourages Jesus’ followers to rest. “Therefore, while the promise of entering his rest is still open, let us take care that none of you should seem to have failed to reach it.” (Hebrews 4:1) The ancient Israelites, according to Hebrews, fail to take God up on his offer of rest because they are disobedient to him. But followers of Jesus receive good news about the rest God promises from the beginning. Because of Christ’s sacrifice, believers are able to accept God’s offer of rest regardless of who they are or where they live. “A Sabbath rest still remains for the people of God; for those who enter God’s rest also cease from their labors as God did from his. Let us therefore make every effort to enter that rest, so that no one may fall through such disobedience as theirs.” (Heb. 4:9-11)
These texts convey a deeper significance to rest, communicated by this notion of “sabbath.” Rest is much more than recuperating from a hectic, tiring week. It is the affirmation of a special relationship people have with God. Rest is a privilege graciously extended by a God who desires his creation to delight in the refreshment he enjoys. The sabbath is holy because it is a day that belongs to God and he graciously chooses to share himself with his creation. He is a generous God who delights in the delight of his people. Rest communicates the character of a holy God who relishes in the act of creation (Proverbs 8:30-31) and desires to commune with it. Rest is the gracious outworking of God’s desire to be in intimate, joyful relationship with humanity and creation.
In 2017, the Harvard Business Review published a summary of recent medical and psychological studies arguing that humans are designed for periods of rest, silence, and deep thought: "Taking time for silence restores the nervous system, helps sustain energy, and conditions our minds to be more adaptive and responsive to the complex environments in which so many of us now live, work, and lead." They also include four tips for cultivating silence and sabbath even in the middle of a busy workplace.
In sum, God sanctifies the seventh day in creation to set it apart from the other days as a day of rest. God does not need to rest, yet finds rest refreshing nonetheless. God rests so his people can partake in his refreshment. Moreover his rest from work fosters his relationship with his people. People take delight in the “very good” creation of God, upon which humanity’s work is meant to build.
In the first two chapters of Genesis, God both works and rests. God also create people to be similar to him: “Then God said, ‘Let us make humankind in our image, according to our likeness; and let them have dominion over the fish of the sea, and over the birds of the air, and over the cattle, and over all the wild animals of the earth.” (Genesis 1:26) God creates people with a job in mind: responsibility over creation. Both the fact that people are created in God’s image and the immensity of the task he entrusts to them prove that God intends his people to be workers. Similarly, he intends his people to be resters, after the pattern he models on the seventh day of creation (Genesis 2:2). God’s dual invitations to work and to rest serve as a validation of the special bond between God, humanity, and creation.
Gordon J. Wenham, vol. 1, Word Biblical Commentary : Genesis 1-15, Word Biblical Commentary (Dallas: Word, Incorporated, 2002), 36.
John I. Durham, Word Biblical Commentary Vol. 3, Exodus (Thomas Nelson, 1987), 413.
Bruce K. Waltke and Cathi J. Fredricks, Genesis: A Commentary (Zondervan, 2001), 72.