Lactantius, Divine Institutes 7.26

We noted a little earlier that when the holy kingdom begins, God will conquer the prince of demons. But once the thousand years of that kingdom — seven thousand in total — begin to draw to a close, he will be loosed once more. Released from custody, he will go out and incite every nation then under the rule of the just, so that they wage war against the holy city. An innumerable host of nations will be gathered from the whole earth and will besiege and surround the city. Then the final wrath of God will fall upon the nations, and He will war against them until not one remains. First He will shake the earth with terrible force; from that convulsion the mountains of Syria will be torn apart, valleys will plunge downward abruptly, and the walls of every city will collapse. God will station the sun for three days so that it does not set, and He will set it ablaze. An immense heat and a great burning will descend upon the perverse and impious peoples. Showers of sulphur, hailstones, and drops of fire will fall. Their spirits will melt away in the heat, their bodies will be crushed by the hail, and they will turn their swords against one another. Mountains will be filled with corpses, fields covered with bones. But for those three days the people of God will be hidden in the hollows of the earth, until God's wrath against the nations and the final judgment have run their course. Then the just will emerge from their hiding places and find everything blanketed with corpses and bones. The entire race of the impious will perish root and branch, and no nation will remain in this world except the nation of God alone. For seven years the forests will stand uncut, no tree felled from the mountains; the weapons of the nations will be burned, and war will be no more, but eternal peace and rest. When the thousand years are completed, God will renew the world: the heavens will be rolled up and the earth transformed. God will transform human beings into the likeness of angels; they will be white as snow and will live ever in the presence of the Omnipotent, sacrificing to and serving their Lord forever. At that same time the second, public resurrection of all will take place, and the unjust will be raised for eternal torments. These are the ones who worshipped things made by hand, who either did not know or denied the Lord of the world and their Father. Their lord, together with his servants, will be seized for punishment and condemned, and with him the whole throng of the impious will be burned in eternal fire before the angels and the just for their own deeds. This is the doctrine of the holy prophets, which Christians follow; this is our wisdom. Those who worship fragile things or defend empty philosophy deride it as foolishness and vanity, because we are not accustomed to defend or assert it publicly. God commands that we keep His secret in silence and within our own conscience, and not contend with those profane people who attack God and His religion inclemently, not to learn but to argue and mock. The mystery must be hidden and concealed most faithfully, especially by us who bear the name of faith. Yet they accuse our silence as if it were a guilty conscience; from that they invent execrable opinions about chaste and innocent people and gladly believe their own inventions.