The purpose of this page speaks for itself. As usual, it shall have as basis God's own inspired word.
The method is top down in regard to scriptural evidence which examines the strongest evidence first and gradually turns to the lesser such toward its conclusion.
4 For he somewhere says like this about the seventh day, "And God rested on the seventh day from all his works," 5 and in this passage again "They shall not come into my rest"; 6 so since it remains that some come into it, and those who heard the gospel before did not come in because of disobedience, 7 . . . 9 So then there remains a sabbath for God's people. 10 For he who has come into his rest is resting from his own works just as God did from his. 11 So let us make it our concern to come into that rest, in order that no one may fall by the same pattern of disobedience. (Byington)
This scripture tells us that some Christians shall enter into this rest of God, the seventh day's rest. That tells us that this period is still not concluded.
Genesis:
What we are told about the sixth day should helps us understand details about its length that may help us determining how long this day isn't.
After God created Eve, the sixth creative day concluded immediately. Then we are told things that happened before Eve's creation that should assist us in understanding how long these days aren't.
Let us list some of these things in a moment. Take the time to realize this following thing — namely, that chapter one is a self contained chapter that focuses on the creation period in terse terms. Chapter two seems to be from the seventh day, but isn't so in all respects.
The divisions of the text into chapters should not be permitted to confuse our understanding of the text. At the beginning of chapter two, we see verses 1-4 that do refer to the seventh day, but from the next verse we return to a different subject entirely:
4 These are the geneses of the heavens and the earth when they were created,—in the day when Yahweh God made earth and heavens. (Rotherham)
In chapter two, incidental things, miscellaneous things pertaining to a variety of subjects are explained, about the earth, rain, the garden of Eden, and Adam, etc. Here we see what Adam's job description was and the edicts he was given against the eating of the forbidden fruit.
The list that is particularly important in regard to understanding the length of time of day six is enumerated here:
19 And the Lord God having formed out of the ground all the beasts of the earth, and all the fowls of the air, brought them to Adam to see what he would call them: for whatsoever Adam called any living creature the same is its name. 20 And Adam called all the beasts by their names, and all the fowls of the air, and all the cattle of the field: but for Adam there was not found a helper like himself. (DRC)
If you believe that God created all the things mentioned in day six in 24 hours, you have a huge list which you think is not impossible since all things are possible to God for sure; still, it is an enormous endeavor:
bring forth the living creature in its kind, cattle
and creeping things,
and beasts of the earth, according to their kinds.
man & woman
All the things above plus populating the earth with them in that one day is surely a huge task.
But, what about the task God gave Adam? Here we are seeing God working at the docile speed of man. He brings the animals to Adam. Next, Adam observes the lifestyle of these and finally decides on some trait of the animal that makes him give that kind its name. And, yet, Eve hasn't been created - we are still in day six, please don't forget!
While all things are possible for God - all things are not possible for man. We take our time. And, if one of us, Adam, must observe each animal kind to give it its name and work through all the various (or many such) kinds of animals to name them, we cannot claim that all of the above takes less than 24 hours!
About time:
One final point about time and God should be remembered though it cannot impact this in any way directly. That is the scripture telling us this:
2 Pet 3:8 But forget not this one thing, beloved, that one day is with the Lord as a thousand years, and a thousand years as one day.
Conclusion:
We are now faced with these Biblical claims on which our faith is founded. We see that Paul tells us that the seventh day hasn't been completed yet and that God's rest day shall still be entered by some - the faithful.
We see that on the sixth day, events that cannot happen in 24 hours take place, not because of God's limitations, but because of our own. God was not in a hurry to finish. He had no time limit to keep except his own.
Why do we then have to fix the creative days to 24 hours human time each? It this really reasonable?
If then each creative day as Paul indicates is a long period of time, it surely is not 24 hours long each. It isn't even 6,000 years long, and how long exactly it is - has been left unstated.
While the first creative day began after the waters were made to surround the earth and in that way fixes the length maximum of each creative day, we still cannot say exactly what that length is. We may perhaps have scientists try to guesstimate their length, but surely we cannot accept the 24 hour human day as the length of these long epochs. Until God sees fit to give us more information, this is the best we can do.