Matthew 24:21 For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.

  22 And except those days should be shortened, there should no flesh be saved: but for the elect’s sake those days shall be shortened.

I've heard strange things, over the years, about what, "those days shall be shortened", actually means.

Some think that the days will be less hours than 24 hours at that time, that's cool, and would make an exciting movie.

However, would less hours per day, really be what the elect, who Jesus mentioned, will need, or hope for, at that time?

Also, saying that it means that the nights will be much longer, is also cool, but would that be what those elect will need?

The LORD had his prophet, Jonah, go and preach against Nineveh:

Jonah 3:1 ¶ And the word of the LORD came unto Jonah the second time, saying,

  2 Arise, go unto Nineveh, that great city, and preach unto it the preaching that I bid thee.

  3 So Jonah arose, and went unto Nineveh, according to the word of the LORD. Now Nineveh was an exceeding great city of three days’ journey.

  4 And Jonah began to enter into the city a day’s journey, and he cried, and said, Yet forty days, and Nineveh shall be overthrown.

However, forty days later, Nineveh was not overthrown, but spared after the people repented.

The LORD changed the prophecy of the forty days.

So, if people repent, or something else moves the heart of the LORD, is it possible that the prophecy of the 1260 days could be shortened?

Revelation 12:6 And the woman fled into the wilderness, where she hath a place prepared of God, that they should feed her there a thousand two hundred and threescore days.

Or the prophecy of the 1290 days?

Daniel 12:11 And from the time that the daily sacrifice shall be taken away, and the abomination that maketh desolate set up, there shall be a thousand two hundred and ninety days.

Why cannot the LORD do with the three and a half years of the great tribulation, like he did with the forty days, and change it?

Or is the LORD forbidden, by us, from reducing the number of days, for some reason that would only be known at that time?