BBC: Genesis 2:1-3
Thus the heavens and the earth were finished, and all the host of them. And 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 2:1-3
So what was begun is now finished. Note that the "heavens and earth" were created at the start and only populated later. Then what does it mean that they "were finished"? Previously they were formless and void (Gen 1:2; BBC) but now everything is "very good" (Gen 1:31; BBC). The filling of His creation pleases God and the establishment of order and dominion pleases Him.
The matter of the seventh day is particularly important for two reasons. One, the entire basis of the Sabbath is to celebrate order, fullness and dominion being established. Christians would do well to recognize that it is not the honoring of the day but the work done during the week that magnifies the Sabbath. It is the work Christ did that causes the celebration of the Lord's Day.
Second, what does it mean for God to rest? If the literal day is meant what does it mean for God to "rest" for "twenty-four hours"? It should be sufficient to show that neither reference is literal but symbolic for a purpose explained within the text. The time reference is given not because God participated to the literal length but to designate the proper human period. God did not truly "rest" for all creation is sustained by Him (Col 1:17; Heb 1:3). So what then is the purpose? To bless and make holy the day.
The Sabbath was made weighty and blessed for man (Mark 2:27) and man reflects this by making holy the day. This is done now by God's Word and His Truth (John 17:17). Make no mistake, the Lord's Day is still to be made holy by the washing of the church by the Word (Eph 5:26).
*The Bible Blogging Commentary is a slow and simple treading of the Scriptures. No quotes from other theologians and no explicit Greek/Hebrew lessons.*