Jerome : (Verses 11-12) Let the desert and its cities lift up: in the houses shall Cedar dwell, praise you inhabitants of Petra, they shall shout from the top of the mountains. They shall give glory to the Lord, and his praise in the islands they shall declare. LXX: Let the wilderness lift up its voice and its towns, the settlements where Kedar dwells. The inhabitants of the rocks will rejoice, they will shout from the mountaintops. They will give glory to God; they will declare his virtues in the islands. Let the desert and its cities raise their voices, as we mentioned earlier. Whether the desert and its villages rejoice, and Cedar, which was once an uninhabitable region beyond Arabia of the Saracens. And the inhabitants of Petra, which is also a city of Palestine. But this signifies that the deserted people of the nations, previously bound by the ignorance of God and the errors of idolatry, should be converted to the praises of the Lord. Whether because Cedar is interpreted as darkness, and according to the Apostle (I Cor. X) Christ is the rock, it is commanded to all believers, that those who were previously in darkness, and now believe in the Lord Savior, shout from the top of the mountains, and openly proclaim Christ, to whom it is also said above (Ad cap. XL, 9): Ascend to the high mountain, you who proclaim the good news to Zion. Lift up your voice with strength, you who proclaim good news to Jerusalem. And I will set his glory among the islands, of which we have spoken before. — Commentary on Isaiah