Isaiah 54:15
Behold, they shall surely gather together, but not by me: whosoever shall gather together against thee shall fall for thy sake.
Cross-reference
Isaiah 54:17 immediately follows with no weapon prospering, reinforcing the outcome that gathered enemies will fail.
Isaiah 8:9 calls on the peoples to be shattered—directly echoing the fate of those who gather against God's people in this verse.
In Isaiah 49:25, God says He will contend with those who contend with you, directly echoing the assurance that enemies who gather will fall.
In Isaiah 60:12, nations that do not serve you will perish, similar to enemies gathering against you falling.
Revelation 20:9 shows fire from heaven consuming the encircling armies—the direct fulfillment of enemies falling because of God's people.
Revelation 20:8 has Satan gathering the nations (Gog and Magog) for battle, echoing the stirring up of strife that leads to their fall.
Revelation 19:19-21 depicts the beast's armies gathered against Christ and destroyed—the ultimate fulfillment of attackers falling.
Revelation 16:14 shows demonic spirits gathering kings for Armageddon, the great battle where God's enemies are defeated as promised.
Zechariah 14:2 has God himself gathering the nations against Jerusalem—a stark contrast to the assurance that such gathering is not from God and ends in their fall.
Zechariah 12:9 promises God will destroy all nations that come against Jerusalem—fulfilling the fall of those who gather against you.
Zechariah 12:3 says Jerusalem will be a heavy stone that injures those who lift it—parallel to the falling of those who gather against you.
Zechariah 2:8 declares that touching Israel is like touching God's own eye—those who gather against you attack God himself and will be judged.
Joel 3:9-14 describes nations gathered for battle in the Valley of Jehoshaphat, where God judges them—a direct parallel to enemies falling.
Ezekiel 38:8-23 details the Gog invasion where enemies gather against Israel and are destroyed, fulfilling the promise that attackers will fall.
Jeremiah 30:16 promises that devourers will be devoured, matching the fate of those who gather against God's people.
Zechariah 14:3 shows God fighting against those nations after they gather—parallel to the enemies falling, though God's direct involvement differs.
Joshua 9:2 records the Canaanite kings gathering to fight Israel—a historical example of enemies uniting against God's people.