By St. Augustine of Hippo
(The City of God, Bk. 19, Ch. 32)
Obadiah, so far as his writings are concerned, the briefest of all the prophets, speaks against Idumea, that is, the nation of Esau, that reprobate elder of the twin sons of Isaac and grandsons of Abraham. Now if, by that form of speech in which a part is put for the whole, we take Idumea as put for the nations, we may understand of Christ what he says among other things, "But upon Mount Sion shall be safety, and there shall be a Holy One." [Ob. 17] And a little after, at the end of the same prophecy, he says, "And those who are saved again shall come up out of Mount Sion, that they may defend Mount Esau, and it shall be a kingdom to the Lord." [Ob. 21] It is quite evident this was fulfilled when those saved again out of Mount Sion — that is, the believers in Christ from Judea, of whom the apostles are chiefly to be acknowledged — went up to defend Mount Esau. How could they defend it except by making safe, through the preaching of the gospel, those who believed that they might be "delivered from the power of darkness and translated into the kingdom of God?" [Col. 1:13] This he expressed as an inference, adding, "And it shall be to the Lord a kingdom." For Mount Sion signifies Judea, where it is predicted there shall be safety, and a Holy One, that is, Christ Jesus. But Mount Esau is Idumea, which signifies the Church of the Gentiles, which, as I have expounded, those saved again out of Sion have defended that it should be a kingdom to the Lord. This was obscure before it took place; but what believer does not find it out now that it is done?