15 “So when you see the abomination of desolation spoken of by the prophet Daniel, standing in the holy place (let the reader understand), 16 then let those who are in Judea flee to the mountains. 17 Let the one who is on the housetop not go down to take what is in his house, 18 and let the one who is in the field not turn back to take his cloak. 19 And alas for women who are pregnant and for those who are nursing infants in those days! 20 Pray that your flight may not be in winter or on a Sabbath. 21 For then there will be great tribulation, such as has not been from the beginning of the world until now, no, and never will be. 22 And if those days had not been cut short, no human being would be saved. But for the sake of the elect those days will be cut short. Mtt. Mat. 24:15-22
For who’s sake will those days be cut short? The elect! Us in Christ! If the elect were not here on earth the days would not have to be cut short. Jeremiah’s prophecy of Jacob’s (Israel’s) trouble coincides with the great tribulation.
The Elect does not necessarily refer to Christians. In the Old Testament the Jews are called the elect on several occasions, for example. Isaiah 45:4 “For Jacob my servant's sake, and Israel mine elect, I have even called thee by thy name: I have surnamed thee, though thou hast not known me.”
Through out history the nation of Israel is at the center of God's plan. Time and time again in the old testament we see a pattern repeated God blesses Israel, Israel turns their back on God, God judges Israel, and Israel turns back to God and the cycle repeats. The time of Jacobs trouble is God's end to this cycle. He will give the devil a free hand and let his judgment poor out on the world for their wickedness. As always God saves a remnanment, the 144,000 who are sealed (elect). The purpose of the tribulation is to turn the hearts of Israel to her Messiah and then he will restore them permanently to a place of blessing.
Ezekiel 39 describes the outcome v22-26 “So the house of Israel shall know that I am the Lord their God from that day and forward. And the heathen shall know that the house of Israel went into captivity for their iniquity: because they trespassed against me, therefore hid I my face from them, and gave them into the hand of their enemies: so fell they all by the sword. According to their uncleanness and according to their transgressions have I done unto them, and hid my face from them. Therefore thus saith the Lord God; Now will I bring again the captivity of Jacob, and have mercy upon the whole house of Israel, and will be jealous for my holy name; After that they have borne their shame, and all their trespasses whereby they have trespassed against me, when they dwelt safely in their land, and none made them afraid.”