Revelation 21:24-25

Revelation 21:24-25. And the nations of them which are saved shall walk in the light of it: and the kings of the earth do bring their glory and honour into it. And the gates of it shall not be shut at all by day: for there shall be no night there.

Shut gates signify war; open gates mean peace. There shall be no more fear of war, no Gog and Magog to gather together to battle, no Armageddon to be dreaded by the glorified Church of Christ, which shall be in perfect peace for ever.