Comments, corrections, and routine editing: absolutely welcomed!
4.4. How long was/is the seventh day?
For in six days the LORD made heaven and earth, the sea, and all that is in them, and rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy (Ex. 20:11)This verse is often cited as proof that the days in Genesis are 24-hour days. But in truth things are not so simple. As a counter example, the eight day “Feast of the Tabernacles” (Leviticus 23:33-43) is meant to parallel and commemorate the Jews wandering in the wilderness—which lasted much far more than eight days. Likewise, God’s providential wisdom in instituting a 6+1 work week might be analogous to the creation “week” rather than a duplicate.
For those of an old-earth perspective, a common view of the seventh day is that it has not ended. That is, both scientifically and theologically what ended after the sixth yôm is God’s act of supernatural creative work. The cosmos was complete. The biodiversity of the earth was complete. No more species—in fact the number of species would now decline by the process of extinction. There are differences of opinion as to when this seventh day ends—in traditional Old Earth Creationism, the seventh day ends when history ends. That is,
Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and there was no longer any sea. I saw the Holy City, the new Jerusalem, coming down out of heaven from God, prepared as a bride beautifully dressed for her husband. And I heard a loud voice from the throne saying, "Now the dwelling of God is with men, and he will live with them. They will be his people, and God himself will be with them and be their God. He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away." He who was seated on the throne said, "I am making everything new!"(Rev. 21:1-5.)implies that at the end of the present age and the onset of the eternal age, God will stop resting and again resume creating. However it does not imply that God has had his feet up ever since He ceased supernatural creation—indeed God is actively involved in His creation—it only means that God ceased creating.
But let’s look at a more concrete argument.
The man went away and told the Jews that it was Jesus who had healed him. And this was why the Jews were persecuting Jesus, because he was doing these things on the Sabbath. But Jesus answered them, "My Father is working until now, and I am working." (John 5:15-17)At first this would appear to support the idea that the seventh day was indeed an ordinary day, and that God rested for 24 hours and then resumed working.
But take a deeper look. Jesus is being criticized for working on the Sabbath. His appeal to his Father’s working only makes sense if it is still the Father's Sabbath (seventh day.) We note also that the Jews did not “counter” Jesus’ argument by saying: "So what, the Father rested for 24 hours after which he resumed working."
Perhaps more compelling is a passage from Hebrews:
For he has somewhere spoken of the seventh day in this way: "And God rested on the seventh day from all his works." And again in this passage he said, "They shall not enter my rest." Since therefore it remains for some to enter it, and those who formerly received the good news failed to enter because of disobedience, again he appoints a certain day, "Today," saying through David so long afterward, in the words already quoted, "Today, if you hear his voice, do not harden your hearts." For if Joshua had given them rest, God would not have spoken of another day later on. So then, there remains a Sabbath rest for the people of God, for whoever has entered God’s rest has also rested from his works as God did from his. Let us therefore strive to enter that rest, so that no one may fall by the same sort of disobedience. (Hebrews 4:1-11)This passage implies that God’s day of rest is ongoing, and salvation permits us to enter into God’s perpetual Sabbath, into his seventh day, which is manifestly longer than 24 hours.