'In those days and at that time, when I restore the fortunes of Judah and Jerusalem, I will gather all nations and bring them down to the Valley of Jehoshaphat. There I will enter into judgment against them concerning my inheritance, my people Israel, for they scattered my people among the nations and divided up my land. They cast lots for my people and traded boys for prostitutes; they sold girls for wine that they might drink.'
The phrase "at that time" refers us back to the Millennial Reign as we saw in chapter two. At the end of this time of peace, we see that ALL nations will be drawn to this valley for judgment. The Valley of Jehoshaphat refers to part of the Kidron Valley that is between the Temple Mount and the Mount of Olives. We see that the nations that come to attack Jerusalem will be judged based on how they have treated God's people (the Jews). We see these same events described by John in Revelation 20. It is important to note, here, that ALL the nations of the earth will come to this valley. There are those who say that the USA will never abandon the state of Israel but God's word says they will. How is this possible? The answer is quite simple in that all of these events will take place after the church has been taken out of the world. Christians are the greatest friends of the Jews and, when we are removed, the USA will turn against Israel.