Ge 2:1 Thus the heavens and the earth, and all the host of them, were finished.

2 And on the seventh day God ended His work which He had done, and He rested on the seventh day from all His work which He had done.

3 Then God blessed the seventh day and sanctified it, because in it He rested from all His work which God had created and made.

The idea that God rested does not imply that God was exhausted and weary after six days of creation. No. Rest simply means cessation. There's nothing more to create. What He wanted to create has all been created. There are no new species to create. There are no new laws of nature to establish, so He ceased.

God ceased from His creative work, but He now proceeds to carry on His sustaining work. At this time, God did not command man to keep the Sabbath. Moses was simply telling His Israelite readers what God did after six days of creation.

After their deliverance from Egypt, God then through Moses instructed the Israelites to keep the Sabbath.

It was to regularly remind them that the God who delivered them from Egypt was the same God who created the universe. They are to constantly bear in mind that their God is both the Creator and the Deliverer.

A special day (the Sabbath) was set aside to emphasize this. In the beginning, God worked and rested. In Egypt, Israel labored and now they are to rest and cease from being slaves. A gift from God.

Now, they are to ceremonially celebrate this during the Sabbath day. Moses wrote these verses to teach Israel to keep and sanctify the Sabbath that God has given to them in memory of His creative and redemptive work.

Note: The marking day for the old creation was the Sabbath for Israel. The marking day for the new creation is the Lord's Day when Christ resurrected from the dead. The Church is not of the old creation, rather, it is of the new creation.