Patristic Wisdom: Looking to the First Sunday in Advent

The word that came to Isaiah son of Amoz about Judea and about Jerusalem: That the mountain of the Lord will be evident in the last days, and the house of God will be at the top of the mountains, and it will be raised above the hills, and all the nations will come to it. And many nations will go and will say, “Come on and let us go up to the mountain of the Lord and into the house of the God of Jacob; and He will proclaim His way to us, and we will walk in it.” For a law will come out from Zion and a word of the Lord from Jerusalem. And He will judge between the nations and will refute a great people, and they will break their swords into plows and their spears into sickles. And no nation will take a sword against a nation, and they will no longer study to make war. (Isaiah 2:1–4 LXX)

The prophetic Spirit foretells the conversion of the Gentiles to God. Then, after these statements about the new law and word, he turns his thoughts towards the new mountain and house of God, to which God will come when those of foreign tribes (he says, Gentiles) who have abandoned the gods of their ancestors come to know the God of the prophets, the one whom the prophets call the God of Jacob. And he gives the clearest sign of the time when these things will be accomplished. The sign will be that the gospel of peace will then be preached to every nation, and there will no longer be districts and governments, neither will nations form factions and rise up against each other, nor will the cities of various nation-states go to war and fight with one another. Everyone everywhere will live in harmony and peace. No longer will those who till the earth have any forethought for swords and instruments of war as in the old days, which they used to practice because of the frequent uprisings of their neighbors. These things were fulfilled right after the coming of our Savior Jesus Christ.…

The mountain of God may be understood in various ways. Like the Jewish people who read the Scriptures literally, one could assume that it is the land of Palestine. But according to the deeper meaning, according to the final word, the high and heavenly and angelic word of God and the divine apostle of the “heavenly” Zion teaches that it is “the Jerusalem above, which is the mother of us all.” This mountain was not manifest to the men of old, but the divine Spirit prophesies that it will be manifest to all nations in the last days, when Christ would “appear to put away sin.” Therefore all nations—“both Greeks and barbarians,” which indeed turn from the error of polytheism and from the literal mountains which were in ancient times thought to be dedicated to demons or to the gods—will strive after the God who is proclaimed in revelation. For this reason, as though speaking one to another, he says: Come, let us go up to the mountain of the Lord and to the house of the God of Jacob, and He will declare to us His way, and we will walk in it. And so the Word promises to the nations that He will make the mountain and the house of God manifest in the heavens and known to all who are instructed.

Eusebius of Caesarea, Commentary on Isaiah 2