This one is easy to miss, I'll give brethren that fact.
In Matthew 24:22 when Jesus was upon the Mount of Olives giving His disciples the signs of the end they asked Him about, (Matt.24:3), He said the time of great tribulation would be shortened for His elect's sake.
What it was shortened to is written in Revelation 9 about the stinging.
Rev 9:2-5
2 And he opened the bottomless pit; and there arose a smoke out of the pit, as the smoke of a great furnace; and the sun and the air were darkened by reason of the smoke of the pit.
3 And there came out of the smoke locusts upon the earth: and unto them was given power, as the scorpions of the earth have power.
4 And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.
5 And to them it was given that they should not kill them, but that they should be tormented five months: and their torment was as the torment of a scorpion, when he striketh a man.
KJV
Those are not real locusts. God uses them as a symbol for how real locusts attack. Per the Book of Joel, they represent "a nation", a certain people at the time of the END that steal the wealth of God's people and deceive many by the LIES that come out of their MOUTHS. That is what that symbolic 'stinging' is actually about. And they will be given to do it for a period of "five months".
Notice especially, they only are allowed to 'sting' those NOT SEALED with God's Seal.