Mark 13:14, 19-20

“But when you see the ABOMINATION OF DESOLATION standing [in the temple sanctuary] where it ought not to be (let the reader understand) then those who are in Judea must flee to the mountains. [Dan 9:27; 11:31; 12:11]

for at that time there will be such tribulation as has not occurred, from the beginning of the creation which God made, until now—and never will [be again]. And if the Lord had not shortened the days, no human life would have been saved; but for the sake of the elect, whom He chose [for Himself], He shortened the days. [Dan 12:1]