As I said earlier, and perhaps you're not catching the significance of this so I'll try to be more detailed this time, there are four texts in the Bible which give prophetic time formulas: two each for a day=year and two each for a day=thousand years.
They are: Numbers 14:34; Psalm 90:4; Ezekiel 4:6; and 2 Peter 3:8.
Of the four, only one goes in both directions, i.e. A = B and B = A. That is 2 Peter 3:8, which tells us that one day is as a thousand years and a thousand years as one day.
Why does it go both ways?
It goes both ways because it gets applied in both directions in the Bible.
Adam lives less than 1000 years, so with that thousand years being likened to a single day, he dies "in" that day, just as God predicted he would. Adam's nearly 1000 years = 1 day.
But creation week is a prophecy in which each of its days represents a millennium to come. Day 1 is prophetic of the first thousand years from creation to just past Adam's time. Day 2 is prophetic of the millennium which follows, the millennium in which Noah's flood takes place. Day 3 represents the next millennium during which the nations develop. Day four is the millennium within which Jesus is born. Day 5 is the millennium in which the Dark Ages begins. And Day 6 is our present era--the era in which God will have a people who perfectly represent His character to the world (man created in His likeness), following which Jesus will come to receive his people. Each day of this week = 1000 years in prophetic time. (There is much more detail here, but I will consider it out of scope for this post.)
The reason for the "as" is that the creation days were literally 24-hour days. But they represented 1000 years each.
If you read 2 Peter 3 carefully, you will see that Peter is cluing his readers in to the fact that Creation must be understood in this prophetic context. Notice this:
2Pe 3:4 And saying, Where is the promise of his coming? for since the fathers fell asleep, all things continue as they were from the beginning of the creation.
2Pe 3:5 For this they willingly are ignorant of, that by the word of God the heavens were of old, and the earth standing out of the water and in the water:
2Pe 3:6 Whereby the world that then was, being overflowed with water, perished:
Here we see Peter addressing Creation. He confirms the creation context by specifying what God had created on days 2 and 3 of creation week. Following this, he says something that should catch our attention: "whereby the world that then was...." That when?
Did you learn in school that the Flood happened within days 2 and 3 of creation week? No? But why not? Isn't that what Peter is saying here?
If we take the text as it reads, that is
exactly what he is saying. But Peter knows it is a hard saying, and he gives us a big clue as to how to understand it.
"But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day." (2 Peter 3:8)
Essentially, Peter is telling us that those days of creation are prophetically linked to the Flood by each representing a thousand years. "One day is with the Lord as a thousand years." And the Flood
does impact days 2 (when it occurred) and 3 (which begins with a world essentially depopulated by the Flood) of earth's week.
