And come up to the valley of Jehoshaphat,
For there I will sit to judge
All the surrounding nations.
Put in the sickle, for the harvest is ripe.
Come, tread, for the wine press is full;
The vats overflow, for their wickedness is great.
Multitudes, multitudes in the valley of decision!
For the day of the Lord is near in the valley of decision.”
—Joel 3:12-14 (NASB)
Through Joel, God uses a past event to describe an even greater event to come. “The valley of Jehoshaphat” refers to a multi-nation invasion of Judah that took place during Jehoshaphat’s reign.  What happened during that event foreshadadows or teaches us what will happen in this even greater, coming event.
In the original battle of Jehoshephat’s day, the oncoming enemy was so vastly superior numerically that it didn’t just frighten Jehoshaphat and the Jews, but sent them into a spiritual revival of sorts, earnestly seeking God’s intervention. In other words, it preceipated a great, spiritual revival among the people. God instructed them to go out to this particular valley to stand opposite this overwhelming, multi-national force, but He did not instruct them to actually engage in battle. He promsied to undertake the entire battle personally on their behalf. Rather, they took up positions and sang praises to the Lord as God threw the enemy into such confusion that they destroyed themselves. The Israelites spent the next 3 days collecting the goods and spoil from the dead before returning home, completely victorious, never having to actually engage in the fight.
This is an example of what the final battle in “the valley of decision” will be like, what we most often refer to as the battle of Armageddon. Preceded by a great spiritual revival wherein Israel finally acknowledges Jesus as their Messiah, He intervenes on their behalf against the numerically overwhelming nations that have all gathered to destroy them. What happened in the days of Jehoshaphat will happen again, but on a much larger scale.
This is one of the irrefutable proofs of God’s return and use of Israel in the Last Days. If the church is meant instead of literal Israel, how would nations gather together to destroy her? Or how would the whole church come to be gathered together in one place — much less Israel — to become engaged in such a confrontation? The literal meaning is not just the best meaning, but the truth: Israel will be regathered and used by God exclusively in the Last Days.†††