It's called "Jacob's Trouble" for a reason. It is there purification before the coming of their King.
Isnt it the punishment of israel for breaking the old covenant constantly worshipping idols and false gods and then rejecting and killing thier king who came to redeem them from that curse like the Old Testament declares ?
“And
when ye shall see Jerusalem compassed with armies, then know that the desolation thereof is nigh. Then let them which are in Judæa flee to the mountains; and let them which are in the midst of it depart out; and let not them that are in the countries enter thereinto.
For
these be the days of vengeance, that all things which are written may be fulfilled.”
Luke 21:20-22 KJV
remember how israel always rejected persecuted and killed the prophets who were warning them about false gods worship and calling them to repent throughout the ot ?
“Therefore also said the wisdom of God,
I will send them prophets and apostles, and some of them they shall slay and persecute: that the blood of all the prophets, which was shed from the foundation of the world, may be required of this generation; from the blood of Abel unto the blood of Zacharias, which perished between the altar and the temple: verily I say unto you, It shall be required of this generation.”
Luke 11:49-51 KJV
the last Hope for the earthly nation of Israel was the messiah who came to restore them and redeem them from the curses of the old covenant after they continually killed and rejected Gods prophets finally the promised son who would save them had arrived thier king came to them pleading with them and thisnis what happened
“And the husbandmen ( Israel )
took his servants, ( the early prophets )
and beat one, and killed another, and stoned another.
Again,
he sent other servants ( the latter messianic prophets foretelling Jesus coming )
more than the first: and they did unto them likewise.
But
last of all he sent unto them his son, ( Jesus the messiah )saying,
They will reverence my son. But
when the husbandmen ( israel ) saw the son, they said among themselves, This is the heir; come,
let us kill him, and let us seize on his inheritance.
And
they caught him, and cast him out of the vineyard, and slew him.
Jesus saith unto them, Did ye never read in the scriptures,
The stone which the builders rejected, The same
is become the head of the corner: This is the Lord's doing, And it is marvellous in our eyes?
Therefore say I unto you, The kingdom of God shall be taken from you, and given to a nation bringing forth the fruits thereof.”
Matthew 21:35-39, 42-43 KJV
The rejection and killing of Jesus is why Jerusalem was destroyed the temple left in rubble never to be rebuilt in 2000 years and th e people were scattered into all nations of earth , that’s what was written all along if they rejected and kept rejecting Gods word meant to save them
rejecting jesus was the last straw and because of it tribulation and depletion resulted about thirty years after Jesus went to heaven when Romes armies surrounded see Jerusalem. Besieged them starved them for three years and then commenced to slaughter everyone and destroy the temple and it’s buildings robbing it for the gold
The great tribulation is that period of time leading up to jerusalems destruction and the subsequent period of mass slaughter and tortures of Christian’s and Jews by Rome . That began a perpetual tribulation on earth until christ returns
the “ Great tribulation period “ was what happened to Jerusalem and the church in those early times the perpetual tribulations Jesus foretold until his second coming is what followed that until Jesus come back it’s why Christian’s today are still killed fornthier beliefs in tbe world but not on that scale like when Christianity began and millions of Jews and chrortoans were slaughtered by Rome and no other be was magically taken up before it happened they all died in the tribulation and were taken into heaven not thier dead body but thoer living spirit
These people are believers on earth and suffered and died in the tribulation
“And when he had opened the fifth seal, I saw under the altar
the souls of them that were slain for the word of God, and for the testimony which they held: and they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and
their brethren, that should be killed as they were, ( the early martyrs ) should be fulfilled.”( the rest of the martyrs till the end )
Revelation 6:9-11
“And it was given unto him
to make war with the saints, and to overcome them: and power was given him over all kindreds, and tongues, and nations. And all that dwell upon the earth shall worship him,
whose names are not written in the book of life of the Lamb slain from the foundation of the world. If
any man have an ear, let him hear.
And he had power to give life unto the image of the beast, that the image of the beast should both speak, and cause that as many
as would not worship the image of the beast should be killed.”
Revelation 13:7-9, 15 KJV
This world holds tribulation for gods people ot always has from abel to John the last author of scripture