Why does Satan gather all the world's armies to the Middle East?
Satan gathers the world's armies into the land of Israel because he believes he can finally and permanently eliminate the Jewish problem. He does not realize that this gathering will become the final battle between himself and Almighty God, where God destroys the assembled armies.
Les teaches that in the battle of Armageddon all the armies of the world have gathered into the land of Israel, and Satan actually feels as though he can finally and once and for all get rid of the Jewish problem. That is the main reason he calls all the armies to the Middle East, not realizing that it is going to turn into that final battle between himself and the Almighty God. God then destroys all these accumulated armies there in the land of Israel with a tremendous hailstorm of hundred-pound hailstones. Les also points to the scriptural analogy of bringing the grapes into a wine vat: as a person walking in the wine vat gets splattered with grape juice, so God will bring all the nations' armies to the Middle East and pack them primarily into the valley of Megiddo, where they will be likened to a wine vat and destroyed. The accompanying river of blood and water will run as deep as the bridles and horses' bits.