... until the times of the Gentiles be fulfilled.

Might it be when the presence of Gentiles are in some way restricted from Jerusalem? And on account that the Jewish Temple had been rebuilt. (In order for 2 Thessalonians 2:4 to occur).

 

And they shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled.​

Jesus does not say in the immediate context what happens after "the times of the Gentiles" but continues his warning prophecy about the destruction. There is the logical reasoning that Jerusalem will be restored, but that is not prophesied by Jesus, nor the Apostles.

Paul in Rom. 11 writes about present blindness until the fullness of the Gentiles comes in. - and so all Israel will be saved. Did the fulness of the Gentiles come in in 1948?

I don't see in the New Covenant Scriptures the reestablishment of Jerusalem as an earthly, Jewish city. Jerusalem is heavenly & all the redeemed comprise Israel - the people of God.

 

Coudl that be referring to when Antichrist signs a treaty fro Muslim/Israel peace?

 

Fulfilled in & by the LORD Jesus Christ & the Gospel.
Acts 3:19-26

23 And it shall come to pass, that every soul, which will not hear that prophet, shall be destroyed from among the people. 24 Yea, and all the prophets from Samuel and those that follow after, as many as have spoken, have likewise foretold of these days. 25 Ye are the children of the prophets, and of the covenant which God made with our fathers, saying unto Abraham, And in thy seed shall all the kindreds of the earth be blessed. 26 Unto you first God, having raised up his Son Jesus, sent him to bless you, in turning away every one of you from his iniquities.​

Believing Israel includes earthly national Christ-believing Jews & Gentiles. Ephesians 2 & Acts 3:25-26, Gen. 12:1-3

After the crucifixion, the Gospel church Israel emerges as the purified Israel, formed on the day of Pentecost with 3,000 Jews from every nation under heaven. The church continues to grow, including priests & Pharisees, before adding Gentiles.

Jeremiah was writing to the exiles, & the "trouble" is probably that recorded in Esther. I believe that we should primarily understand prophecy in its context, and then as interpreted by Jesus & the Apostles.

Malachi (one of the post-exile prophets) is preparing the Jews for the coming of the Messiah, preceded by John. But note the last verse in the OT -

5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord: 6 and he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.​

 

Didn't you read the Scriptures I quoted? Acts 3 makes it clear that the promises to Abraham were & are being fulfilled in & by the LORD Jesus Christ through the Gospel.

 

We need to distinguish between the political nation, Israel, & "my people, Israel." God has a people whom he calls "my people" with the oft repeated expression, "you will be my people, I will be your God" in various forms, -

Jer. 31:33 but this shall be the covenant that I will make with the house of Israel; After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.​

including references to Gentile inclusion -

Hos. 2:23 And I will sow her unto me in the earth;
and I will have mercy upon her that had not obtained mercy;
and I will say to them which were not my people,
Thou art my people;
and they shall say, Thou art my God.

Zec. 2:10 Sing and rejoice, O daughter of Zion: for, lo, I come, and I will dwell in the midst of thee, saith the Lord. 11 And many nations shall be joined to the Lord in that day, and shall be my people: and I will dwell in the midst of thee, and thou shalt know that the Lord of hosts hath sent me unto thee.

2 Cor. 6:16 and what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people.
​

Many thousands of the people of Israel responded to John's preaching, & were sent to follow Jesus. Also many responded to Jesus' preaching, while numbers are beyond counting after Pentecost, - 3,000, 5,000, multitudes both of men and women, and the number of the disciples multiplied in Jerusalem greatly; and a great company of the priests were obedient to the faith.

When Elijah complained he was alone, God assured him of 7,000, also quoted in Rom. 11.

The truth is that the people of Israel did believe, in vast numbers, & formed the community called the "church." God's purpose for his redeemed people was clearly not the physical nation, but the holy nation, comprising believers, both of Israel & the Gentiles. He is gathering them, us, by the Gospel. The nation in the once promised land is irrelevant to prophecy - see Hebrews 11 & 12, Gal. 4. The Gospel promised land is the NH&NE. 2 Peter 3.

The "millennium" is the present Gospel age which Peter explains is the time for repentance, which will come to an end when Jesus returns. 2 Peter 3.

 

Jesus has not yet installed His Kingdom in full here upon this earth, and so is not the messianic Age!