LeavingQuietly: My personal opinion (and that's all it is, an opinion): Gog of Magog in Ezekiel 38 & 39 have no fulfillment in our time period. For it to have fulfillment, all those of natural Israel would have to be regathered to the land of Israel first. Otherwise, God would be lying.
Yes, God has spoken of Gog in many places (Zechariah 12, 14, Revelation 11), and Ezekiel, in chapter 38, says it will be in the "latter years," not in the "final part of the years." And this has always referred to the last days. Also, you said that throughout history only the King of Babylon has ever come from the north to conquer Jerusalem. This is not really true as the Romans also came through the northern parts to destroy Jerusalem. The Greeks also came from the north, but did not destroy the city. The fact that it remains unfulfilled means 1) that the prophecy was false; or 2) that it is unfulfilled. The third option, that it was fulfilled, but we just don't know when, is unlikely given that so many prophets have written of it.
John, when writing of the great assault from the north, gives us this clue:
This calls for a mind with wisdom. The seven heads are seven mountains on which the woman sits. They are also seven kings. Five have fallen, one is, the other has not yet come; but when he does come, he must remain for a little while. The beast who once was, and now is not, is an eighth king. He belongs to the seven and is going to his destruction. (Revelation 17:9–11)
The eighth king, which once was, and then was not, resurrects to become the eighth king. Some have thought this was the Roman Empire, but this is highly unlikely. Both Ezekiel and Zechaiah list the nations that will make up the Antichrist's kingdom, and they describe the great enemy of God as the nations surrounding Israel and directly to the north. Thus, the nation that will most likely be the origin of the Beast is the Muslim Caliphate in Turkey. The Caliphate existed between the time Rome fell and consisted of the nations Ezekiel spoke of. It ended in 1923. Thus, it was, is not, yet will be again. And that's the goal of ISIL -- to reestablish the Caliphate.
So what are the seven kings that come before? According to Joel Richardson, author of The Islamic Antichrist and The Mideast Beast, they are 1) Egypt, 2) Assyria, 3) Babylon, 4) Persia, 5) Greece, 6) Rome, and 7) the Ottomon, which lasted until 1909, when Turkey was established and, in 1923, the Caliphate was officially abolished. The Roman Empire, including the Eastern Byzantine, lasted all the way until 1453, when it was conqered by the Turks. Thus, if correct, Gog will be the eighth king. John also saw that this kingdom suffered a serious head wound and was miraculously healed, creating wonder in the people of the earth. Because the Bible is Jerusalem-centric, Richardson notes, we must keep in mind that this wonder would mostly be in the minds of the people of the Middle East Muslims. He would be so powerful that they would say, "Who is like the Beast? Who can make war against him?"
The most convincing evidence Richardson supplies is the number of great similarities between Islamic eschatology and Christian eschatology. Only the good guys in Islamic prophecy are the bad guys in Christian prophecy and vice versa. In Islamic eschatology, it's the Jews who are the great enemy, and the Mahdi who is the great deliverer; while in Christian eschatology it's exact opposite. Also, the Mahdi will be supported by a great prophet claiming to be Jesus Christ. He will do great miracles and yet "break the cross" and abolish the Islamic tax on non-Muslims. In other words, he will do great wonders, but tell Christians emphatically that while he is indeed the Messiah, he is not the Son of God, nor is he God. And by abolishing the tax, Jews and Christians will be in the position of either accepting Islam or...else, being beheaded. Yet John writes:
And I saw the souls of those who had been beheaded because of their testimony for Jesus and because of the word of God. They had not worshiped the beast or his image and had not received his mark on their foreheads or their hands. (Revelation 20:4)
Richardson's book was published in 2009, five years before ISIL shocked the world by beheading journalists, aid workers, Christian civililans, including small children. Obviously, I can't explain all the reasons why Ezekiel's prophecy is unfulfilled, but hopefully this will be enough. And BTW, all of Israel wasn't to gather to Israel -- only Judah. Isaiah writes of our day:
And in that day there shall be a root of Jesse, which shall stand for an ensign of the people; to it shall the Gentiles seek: and his rest shall be glorious. And it shall come to pass in that day, that the Lord shall set his hand again the second time to recover the remnant of his people...and he shall set up an ensign for the nations and shall assemble the outcasts of Israel and gather together the dispersed of Judah from the four corners of the earth. (Isaiah 11:10-12)
Since the Lord gathered his people in the days of the Babylonian conquest, Isaiah is writing of a time in the future when the Lord will raise up a "root of Jesse" to the Gentiles, and that his death would be glorious. And in that day, the Lord would set his hand "a second time" to recover the remnant of his people, the dispersed of Judah. Eventually he will gather the rest of Israel, but for now it's a "remnant," the "dispersed of Judah." Why only Judah? Because in Genesis 49, Jacob (Israel) blessed each of his children, and he gave the land to Judah, who would maintain the scepter. Thus, Jesus, being the direct descendent of King David, through Mary, had the right to govern. Joseph actually received the birthright, and his birthright was far greater.
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