Augustine of Hippo
"When the thousand years are ended, Satan will be released from his prison and will go out to deceive the nations at the four corners of the earth, Gog and Magog, and to gather them for battle. Their number is as the sand of the sea."
At that time, therefore, he will deceive precisely in order to draw them into this war. For before this also he deceived in every way he could, through the multitude and variety of evils.
It is said that he "will go out," that is, he will pass from hidden hatred to open persecution.
This will be the last persecution which the holy Church, that is, the city of Christ, will suffer throughout the whole earth before the coming of the Last Judgment. It will suffer from the whole city of the devil, while both are still on earth.
Read more (229 words)
By the nations called Gog and Magog we should not understand certain barbarians inhabiting some part of the earth, such as the Getae and Massagetae, as some think because of the similarity of letters in their names.
Nor should we understand other foreign nations not under Roman rule. For they are shown as living throughout the whole earth when it says: "He will go out to deceive the nations at the four corners of the earth," and then adds, "Gog and Magog."
The meaning of these names in translation is this: Gog means roof, and Magog means from under the roof. It is as though there were a house, and one who comes out of the house.
These, then, are the nations in whom, as we showed above, the devil is shut up as in an abyss. He himself, as it were, comes forth and goes out from them. They are the roof, and he is from under the roof.
But if we refer both names to the nations, and not one to them and the other to the devil, then they will be both roof and from under the roof.
They are the roof because the ancient enemy is now shut up in them and is, in a certain way, covered by them. They are from under the roof when they pass from hidden hatred to manifest hatred.