1. Rev 16:14 They are spirits of demons performing miraculous signs, and they go out to the kings of the whole world, to gather them for the battle on the great day of God Almighty. Ezek 38:4 I will turn you around, put hooks in your jaws and bring you out with your whole army–your horses, your horsemen fully armed, and a great horde with large and small shields, all of them brandishing their swords.
In Rev 16 we see the spirits of devils gathering the world to battle, Ezek 38 we see God putting hooks in Gog’s jaw to drag him forth. However, if Rev 16 is one of the judgements of God upon the world, then God is the instigator of the spirits of the demons, and sends them out to gather the armies of the world together and therefore, then God is really responsible in both passages for bringing the armies to war.
2. Rev 16:16 And he gathered them together into a place called in the Hebrew tongue Armageddon. Ezek 39:4 Thou shalt fall upon the mountains of Israel, thou, and all thy bands, and the people that is with thee: In Rev 16 they are gathered together at Armageddon, in Ezek 39 they fall on the mountains of Israel.
However, in Ezek 38:9 we are also told ” Thou shalt ascend and come like a storm, thou shalt be like a cloud to cover the land, thou, and all thy bands, and many people with thee.” One in six will survive this battle, so it is still possible for the survivors of this war to participate in the Battle of Armageddon, (which also involves Jerusalem,) and still be judged again by God on the mountains of Israel.