I thought I would just elaborate, as I did Sunday, on what God resting on the seventh day actually means in the ancient Near Eastern world.
First, it doesn't mean that God got tired and needed a break from all that work He did in creation. It also doesn't mean that God stopped creating. The picture isn't literal. It's attempting to convey something important (something connected to the rest of the narrative and the book as a whole) with the imagery of God ceasing to labor and resting. And that something is sovereignty. It conveys that God is in complete and absolute control with no threat of chaos/evil to challenge His throne. Chaos cannot overcome Him. It is not even a concern. Hence, He rests upon His throne (i.e., within His cosmic temple).
We see this concept in the surrounding literature as well. After Baal defeats Yam, his temple made and purified, he finishes his conquest and rests in his temple. This motif is common in the ancient Near East, and it mimics the actions of a human king, who after defeating his foes, may rest in his palace, having no more enemies to conquer.
One must remember that a temple of a god is equivalent to the palace of a king. The king rests in his palace when war is no longer a threat, when he has gained victory over destructive forces and has no more concern of them. Likewise, a god rests in a temple when he has overcome chaos, and like the king, has nothing else to worry about in terms of threat of chaos.
In Enuma elish, Marduk battles Tiamat, the primordial waters (deep waters often function in ancient Near Eastern literature as a symbol of chaos--in fact, one might say it is the primary symbol of chaos in the ANE world). After he kills Tiamat and forms the cosmos with her body, he constructs his temple as the "dwelling place of his leisure" and a "stopping place" for the gods, where they declare that within this temple, "we will find rest" (6.51-52).
What the rest and ceasing from labor teaches in Genesis 2 is that God is sovereign over chaos/evil. It is not a threat to Him, nor to His purposes. He has no concern of it in terms of it "winning." The account itself does not present chaos as personified, as do the other accounts both within the poetic literature of the Bible and in many texts outside of the Bible, but it is instead a condition of the earth that threatens the existence of mankind. God creates/orders the world so that those conditions no longer exist. Mankind can thrive. There is no threat of him being diminished. As this creation account is the view from heaven, from God's perspective, it is not negated by what we know will be coming in the chapters that follow. Instead, it puts them into perspective.
Walton summarizes the idea of šābat "rest" nicely:
The verb šābat describes a transition into the activity or inactivity of nûha. We know that when God rests (ceases, šābat) on the seventh day in Genesis 2, he also transitions into the condition of stability (nûha) because that is the terminology used in Exodus 20:11 . . . His rest is also located in his “resting place” (mĕnûhâ) in Psalm 132, which also identifies it as the temple from which he rules. After creation, God takes up his rest and rules from his residence . . . When the deity rests in the temple it means that he is taking command, that he is mounting to his throne to assume his rightful place and his proper role.
This same thing is conveyed in the only text in the Gospels that tells us that Jesus slept. And what is the context of that sleeping? The disciples are in the middle of the sea in a storm. The picture of the chaotic waters that threaten God's purposes is brought to life. And what happens? Jesus is sleeping. There is no concern that the power of chaos has any real ability to thwart God. Instead, Jesus, as God, simply gets up, commands the waters and the storm to be silent, and it immediately is. Thus, the Lord conveys the idea to them, and to us, that He is sovereign and nothing is so powerful that it is any real threat either to Him or to His work.
Hence, the rest conveys sovereignty, which ironically is the exact opposite of being tuckered out and weak because of labor. God is so strong that there is nothing for Him to fret about. And Auctor wants us to know that we are moving toward that rest, but we have not yet entered it. We still need to fear being found outside of Him, since He is the only one who has nothing to fear from chaos/evil/death. We have everything to fear if we are found outside of Him. So we need to keep a sharp eye on whether we are pursuing God through faith in Christ and the doing of good and the refraining from evil that evidences His lordship over our lives.
As I said Sunday, Christ is the only One who is saved. He's the only One who has accomplished salvation by His works. Hence, we have to take hold of His salvation, His safety from chaos, by letting Him take hold of us as our Lord. Whatever He owns is saved with Him, so as long as we are in Him, we are saved too. If we are found outside of Him, there is no hope of salvation, as only He is saved. Hence, since we are still in the wilderness (neither bound to the slavery of Egypt nor free from the chaos of temptation and unbelief in the promised land), we have only to concern ourselves ("fear" as Auctor puts it) with whether we have fallen short of having a genuine loving and submissive relationship with Christ. He has entered that rest. He has nothing to fear, but we have not entered it yet, so we must be on guard against everything that seeks to move us from the sphere of Christ's Lordship to the sphere of chaos, where we can be destroyed.
Therefore, let us fear if, while a promise remains of entering His rest, any one of you may seem to have come short of it. For indeed we have had good news preached to us, just as they also; but the word they heard did not profit them, because it was not united by faith in those who heard. For we who have believed enter that rest, just as He has said, "As I swore in My wrath, They shall not enter My rest," although His works were finished from the foundation of the world. For He has said somewhere concerning the seventh [day]: "And God rested on the seventh day from all His works"; and again in this [passage], "They shall not enter My rest." Therefore, since it remains for some to enter it, and those who formerly had good news preached to them failed to enter because of disobedience, He again fixes a certain day, "Today," saying through David after so long a time just as has been said before, "Today if you hear His voice, Do not harden your hearts." For if Joshua had given them rest, He would not have spoken of another day after that. So there remains a Sabbath rest for the people of God. For the one who has entered His rest has himself also rested from his works, as God did from His. Therefore let us be diligent to enter that rest, so that no one will fall, through [following] the same example of disobedience. For the word of God is living and active and sharper than any two-edged sword, and piercing as far as the division of soul and spirit, of both joints and marrow, and able to judge the thoughts and intentions of the heart. And there is no creature hidden from His sight, but all things are open and laid bare to the eyes of Him with whom we have to do. (Heb 4:1-13)
 Walton, The Lost World, 73–75. See Sarna’s comments (Genesis, 15) that “God, through His creativity, has already established His sovereignty over space; the idea here is that He is sovereign over time as well.”