If those days had not been cut short, no one would survive
In the Olivet Discourse Jesus tells us that the Great Tribulation will begin when we see the abomination that causes desolation. The abomination that causes desolation is the event that occurs when the Antichrist sets himself up in God's temple, proclaiming himself to be God (Daniel 9:27 and 2 Thessalonians 2:4). Jesus then describes what will be happening during the Great Tribulation and explains that if that time of persecution were not cut short, no one would survive.
So when you see standing in the holy place 'the abomination that causes desolation,' spoken of through the prophet Daniel - For then there will be great distress [tribulation], unequaled from the beginning of the world until now - and never to be equaled again. If those days had not been cut short, no one would survive, but for the sake of the elect those days will be shortened (Matthew 24:15, 21-22).
What does Jesus mean when He says, those days will be shortened?
From the prophet Daniel, we learn that during this period the saints will be oppressed for a time, times and half a time (3 ½ years) which is the full time span of the Great Tribulation.
He will speak against the Most High and oppress his saints and try to change the set times and the laws. The saints will be handed over to him for a time, times and half a time (Daniel 7:25).
Daniel, also indicates that from the abomination that causes desolation, in the the middle of the seven until the end there will be (3 ½ years). This again is the full time of the Great Tribulation.
He will confirm a covenant with many for one 'seven.' In the middle of the 'seven' he will put an end to sacrifice and offering. And on a wing of the temple he will set up an abomination that causes desolation, until the end that is decreed is poured out on him (Daniel 9:27).
In Revelation we see this same idea expressed in another way. The Antichrist will be given power to make war against the saints for forty-two months (3 ½ years). Once again, this is the full time of the Great Tribulation.
The beast was given a mouth to utter proud words and blasphemies and to exercise his authority for forty-two months. He opened his mouth to blaspheme God, and to slander his name and his dwelling place and those who live in heaven. He was given power to make war against the saints and to conquer them. And he was given authority over every tribe, people, language and nation (Revelation 13:5-7).
Therefore, Scripture indicates in several places that the Great Tribulation will last (3 ½ years) a time, times and half a time, 1,260 days forty-two months and from in the middle of the seven. Since we know all Scripture is true, we must find an interpretation in which the persecution will last the full 3 ½ years and also mean that those days will be shortened.
When Jesus said, for the sake of the elect those days will be shortened, what did he mean?
For then there will be great distress, unequaled from the beginning of the world until now--and never to be equaled again. If those days had not been cut short, no one would survive, but for the sake of the elect those days will be shortened (Matthew 24:21-22).
Jesus is saying that if the Antichrist were not stopped at the end of the 3½ years of persecution no one would survive. In other words, if the Great Tribulation were allowed to continue until its natural conclusion say another year for example - then, no one would survive. But, for the sake of the elect those days will be shortened. Christ will return at the end of the 3½ years, gather the elect and defeat the Antichrist before everyone is killed.
Therefore, the Great Tribulation will be stopped at the Second Coming. Paul also expressed this.
For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air (1 Thessalonians 4:16-17).
Paul implies that many will be killed during the Great Tribulation. However, some will be left alive until the coming of the Lord. Those that are left alive will be part of the Resurrection when they are caught up (the rapture) together in the clouds, with the dead in Christ, to meet the Lord in the air.
Richard H Perry