Answer:
Good question.
As you read through the Old Testament you always see God taking Israel back even after they run after idols and reject their true God. The book of Hosea even gives the example of a prostitute being bought back again after she ran away as a sign of God’s love for His people.
This last 2,000 years has been a dispensation of grace and it has mainly been toward the Gentile nations. It is rare you see a Messianic Jew (although my ministry partner is one) because the Jewish people did reject Christ. However, the great tribulation and end times will be when God again reveals Himself to the Jewish people and it is a time when they will become aware of things like never before and we will see thousands of Jews coming to know Christ (although it will cost them their very lives to do so).
So, to answer your question – during this time of God dealing with the nation of Israel if He did not protect the 144,000 the Bible says every single Jew would be wiped out. God divinely protects these sealed ones (12,000 from every tribe), but millions will probably be martyred by antichrist and his armies.
Revelation 7:1-10 And after these things I saw four angels standing on the four corners of the earth, holding the four winds of the earth, that the wind should not blow on the earth, nor on the sea, nor on any tree. And I saw another angel ascending from the east, having the seal of the living God: and he cried with a loud voice to the four angels, to whom it was given to hurt the earth and the sea, Saying, Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads. And I heard the number of them which were sealed: and there were sealed an hundred and forty and four thousand of all the tribes of the children of Israel. Of the tribe of Juda were sealed twelve thousand. Of the tribe of Reuben were sealed twelve thousand. Of the tribe of Gad were sealed twelve thousand. Of the tribe of Aser were sealed twelve thousand. Of the tribe of Nepthalim were sealed twelve thousand. Of the tribe of Manasses were sealed twelve thousand. Of the tribe of Simeon were sealed twelve thousand. Of the tribe of Levi were sealed twelve thousand. Of the tribe of Issachar were sealed twelve thousand. Of the tribe of Zabulon were sealed twelve thousand. Of the tribe of Joseph were sealed twelve thousand. Of the tribe of Benjamin were sealed twelve thousand. After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands; And cried with a loud voice, saying, Salvation to our God which sitteth upon the throne, and unto the Lamb.
Matthew 23:37-39 O Jerusalem, Jerusalem, thou that killest the prophets, and stonest them which are sent unto thee, how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not! Behold, your house is left unto you desolate. For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
Very good question,
Pastor Brad