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 always loved that verse because over and over again, we are told that the earth will go through horrible punishment for 7 years, during the Tribulation, but, like any loving parent, God finds a way to shorten our suffering, so that we will indeed go through 7 years of punishment, just that some of that punishment will occur with 16 hour days. I suspect that at the time of the creation of the earth, the earth rotated at that speed. 16 hour days may be what God designed at first.