The Old Testament says that if the Jews were faithful to God, and His Christ, they would be first among the nations.
“It shall happen, if you shall listen diligently to the voice of Yahweh your God, to observe to do all his commandments which I command you this day, who Yahweh your God will set you on high above ALL the nations of the earth:”
Deut 28:1 WEB
Also it was clear that if Israel was not faithful to the Lord their God, that the Jews would be dominated by the gentiles, the nations of the world, Deut 28:15ff, 36-65, etc.
Moses made it clear that Israel was NOT faithful!
“They have dealt corruptly with him, they are not his children, it is their blemish;
They are a perverse and crooked generation.”
Deut 32:5 WEB
When Israel rejected their own Messiah, they were only doing what was anticipated by God and all their prophets. So Jesus said,
“ 32 Fill up, then, the measure of your fathers. 33 You serpents, you offspring of vipers, how will you escape the judgment of Hell?”
Mtt 23:32 nf
Jesus prophesied the destruction of
Jerusalem and its domination by
the nations for generations.
This is discussed in several gospel passages. Jesus says that when they see Jerusalem surrounded by armies, that they will know its desolation is near, Lk 21:20. The Christians did know that, and escaped the siege some forty years later. Then Jesus points to the horrors of those days and also a distant turnaround among the Jews.
“They will fall by the edge of the sword, and will be led captive into all the nations. Jerusalem will be trampled down by the Gentiles, UNTIL the times of the Gentiles are fulfilled.”
Lk 21:24 WEB
So there WILL BE a time in the future when domination by the gentiles, that is to say the nations of the world, will end.
So what is the purpose In these things?
The answer is given in Romans chapters 9-11. However you can read tens of thousands of pages of commentary and never notice the clear answer and summary. Paul has talked in detail about the wickedness and unbelief of his fellow Jews. He cautions us gentiles, especially in Romans 11 to not be arrogant against the Jews. They are the natural olive tree into which we as gentiles (the nations) as wild olive branches have been grafted, Rom 11:17-22. Paul tells us of the Jews,
“They also, if they don’t continue in their unbelief, will be grafted in, for God is able to graft them in again. ”
Rom 11:23 WEB
We should not be ignorant Paul says
“… that a partial hardening has happened to Israel, until the fullness of the Gentiles has come in, 26 and so all Israel will be saved. …”
Rom 11:25-26 WEB
He is contrasting physical Israel with the gentiles.
“Now if their fall is the riches of the world, and their loss the riches of the Gentiles; how much more their fullness?”
Rom 11:12
Unless otherwise noted, Scriptures are the WEB World English Bible, a copyright free revision of the original ASV American Standard Version 1901
nf is my own translation based on the WEB.