Some people have suggested that based on the verse below, one day is equal to a thousand years.
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 (KJV)
They then continue and say that the six day creation, is therefore 6,000 years, opening the door for evolution, etc. Sigh.
The above verse is taken out of context. The phrase "one day is as a thousand years" is actually a reference to how God sees time.
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. The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.
- 2 Peter 3:8-9 (KJV)
That phrase is an explanation that with God some things happen quick, and sometimes they don't. For example, Jesus said the "kingdom of heaven is at hand", but at the same time, that was 2,000 years ago.
From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.
- Matthew 4:17 (KJV)
The phrase Peter uses is called a simile, which means "a figure of speech".
The verse below from Psalms confirms this.
For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night.
- Psalms 90:4 (KJV)
On top of that, the "one day equals..." assignment for prophecies is already used for something else.
And when thou hast accomplished them, lie again on thy right side, and thou shalt bear the iniquity of the house of Judah forty days: I have appointed thee each day for a year.
- Ezekiel 4:6 (KJV)
1 day = 1 year
1 week = 7 days = 7 years
1 month = 30 days = 30 years
1 year = 360 days = 360 years
With that insight the prophecies from the Old Testament (especially from Daniel) take on a whole new meaning.
Jesus used the "1 day = 1 year" rule as well.
And he said unto them, Go ye, and tell that fox, Behold, I cast out devils, and I do cures to day and to morrow, and the third day I shall be perfected.
- Luke 13:32 (KJV)
Jesus was clearly speaking of his 3 1/2 year ministry in terms of years here, not days.