This beautiful valley of Jezreel/Megiddo will never see an end-time battle
In defence of the sidelined God Jehovah, Creator of the Universe and Father of Humanity
The Great Tribulation!
First up, the genesis of that phrase was the mouth of Jesus during a conversation with his disciples about the destruction of the Temple as part of the entire structure of 1st covenant Israel and the end of their special relationship with their Creator*:
* Isaiah 43:1: And now this is what Jehovah has said, your Creator, O Jacob, and
your Former, O Israel: “Do not be afraid, for I have repurchased you. I have called
[you] by your name. You are mine.
Isaiah 43:15: I am Jehovah your Holy One, the Creator of Israel, your King.”
This was said to Israel prior to their destruction by Babylon, assuring them of Jehovah's love and a return to the promised land after their 70-year exile.
Jeremiah 31:35-37 further emphatically guaranteed the permanence of their relationship with Jehovah who would rather remove all the laws of the universe than to let go of His firstborn son Israel.
When did the Great Tribulation begin?
At the time Jehovah's only-begotten angelic son Michael the Archangel stood up again.
For all the exquisite, exiting and satisfying details please access this link.
Here then the origin of that phrase in Matthew 24:
21 "For then there will be great tribulation, such as has not been since the beginning of the world <2889>* until this time, no, nor ever shall be.
Jesus had said this before he had saved Israel by proxy in place of the heavenly
only-begotten actually offered as per John 3:16,
* Whose/Which world?:
Government, order of things, decoration, ornament: Israel! who else? link
Here, from the time of Jesus, Israel's Lord and Atonement, all the way to Revelation 7, Israel's incredible, but very real Great Tribulation continues:
13 Then one of the elders answered, saying to me, "Who are these arrayed in white robes, and where did they come from?"
14 And I said to him, "Sir, you know." So he said to me, "These are the ones who come out of the great tribulation, and washed their robes and made them white in the blood of the Lamb.
Who are those still washing their robes?
Individual transgressors against the 1st covenant needing to demonstrate their personal acceptance of a redemption already granted Israel through Jesus. — link.
Note that the Apostle Paul still needed to demonstrate his own personal acceptance of Israel's redemption through Jesus the lamb of God (John 1:29) —– Romans 8:23:
Not only that, but we also who have the firstfruits of the Spirit,
even we ourselves groan within ourselves, eagerly waiting
for the adoption, the redemption of our body. NKJV
How do Christianity handle this momentous event?
Variously, as best explained here: https://en.wikipedia.org/wiki/Great_Tribulation where the GT has either already happened or is yet to occur in some end-time scenarios of various shades.
The people I was formerly associated with have it both ways with Israel's demise at the hands of the Romans the diminutive type of the other allegedly global one.
The Great Tribulation is about Jehovah's continuing wrath with Israel* in the flesh,
which began from their destruction by the Romans in 70 CE continuing right up to
the very threshold His kingdom of the 1000 years, whereas Armageddon is the battle
of confining all the rebellious Angels of the heavenly realm* including their leader
Devil (slanderer) or Satan (resister) for the 1000-year duration of that kingdom,
to be personally dealt with by Him who originally assigned them to helpfully engage
with humanity during His earth-related rest day.
* Matthew 24:21
* Revelation 12:7-9 and 20:1-3
It may enhance your continuing research and save me going on about it here, if you were to avail yourself of the submenu pages especially this more detailed tribulation-related one: link.
Please continue sussing out God and His purpose