Another designation of the word elect in the Bible, references tribulation saints.
These are NOT Christians trying to endure to the end to keep their soul's spiritual salvation. These are tribulation saints trying to endure to the end by staying alive physically during the 7 years of Daniel's 70th week. Matthew 24:13 is a reference to the physical, not the spiritual salvation of tribulation saints.
This is NOT a reference to the gospel of grace of God, that New Testament, born-again Christians are called to preach to individuals. Rather, this is a kingdom gospel, that involves the preaching of an arriving KING who will set up a physical KINGDOM. This is why Matthew 24:14 uses the phrase: "the gospel of the KINGdom."
Again, Matthew 24:20 is NOT referencing New Testament born again Christians, as we have never, and will never be concerned with keeping the sabbath. This is referencing the elect, tribulation saints.
The phrase: "the very elect" is a reference to tribulation saints.
Many Christians wrongfully believe that Matthew 24 is teaching that the church will go through the tribulation. However, IF you make Matthew 24 for the church, you've got a major problem. That is: it becomes possible for God's elect to lose what God has elected to give them.
Therefore, Matthew 24 cannot be applied to the church, nor can it be applied to a New Testament Christian's spiritual salvation. Christians will NOT lose their salvation. Romans 8 makes it very clear that NOTHING can separate believers from Christ. It also plainly states that there is NO condemnation that can be brought against believers.
The elect in Matthew 24 is referencing tribulation saints. The reason being is that during Daniel's 70th week, people would be dying at a rapid pace, IF God doesn't shorten the days.
The reason God shortens the days is so the elect tribulation saints will survive and be saved physically. The elect can then live to enter into Christ's promised physical, millennial KINGDOM.
This is NOT a reference to Christians during the "church age" because we would want MORE hours in a day to witness and reach the lost for Christ. Right now, the concern is saving souls for eternity. But in Matthew 24 it's a reference to saving the physical lives of tribulation saints, whom God terms as "HIS ELECT."