Revelation 20:8

At that time the devil will have a single objective in his deception, namely, to bring on this battle, rather than deceive by the multifarious means of his previous malice. The expression "will go forth" means that his secret hatred will blaze out into open persecution. For this is to be the very last of all persecutions immediately preceding the very last of all judgments—a persecution that Holy church, the worldwide city of Christ, is to suffer at the hands of the worldwide city of the devil, in every place where the two cities will then extend. The peoples John calls Gog and Magog are not to be thought of as some definite barbarians dwelling in a certain part of the earth, such as the Getae and Massagetae (as some have imagined on account of the initial letters), or any other foreign tribes beyond the pale of the Roman Empire. John clearly indicates that they are to be everywhere in the world, "nations that are in the four corners of the earth, Gog and Magog." Of these names I am told that, literally, Gog means "a roof" and Magog "from the roof." Thus we may take the words to mean an "abode" and a "person issuing from this abode" and, therefore, "the peoples in whom the devil abides as in an abyss" and "the devil himself, lifting himself up and coming out of them." They are the "roof," and he is "from the roof." If … we apply both names to the peoples (rather than the first to them, the second to the devil), then they are the "roof" because the ancient foe is now shut up and roofed over in them, and they will issue "from the roof" when their concealed hatred bursts forth and is revealed in the open.