John Calvin Commentary Isaiah 49:11

"And I will make all my mountains a way, and my highways shall be exalted." — Isaiah 49:11 (ASV)

And I will place all my mountains. Here he directly and expressly discusses the return of the people; for he would have promised such great happiness to the Church in vain if the people were not to be restored to their former liberty. The meaning is that he will remove every obstacle and hindrance that might prevent the return of the people; and that he will render the "mountains" passable, which appeared to be impassable; and, in short, that he will level both the mountains and the valleys, so that their return to Judea may be facilitated.

Thus, when the Church is about to be completely restored, no obstructions, however great and formidable, can hinder God from being finally victorious. Besides, when he calls them "my mountains," he not only means that he has an absolute right to command them to afford a passage to his people, but declares that he will be the leader of the expedition, as if he would march along with the Jews and accompany them on the journey.

In like manner, it is said in another passage, that he passed through Egypt and rode on the high places of it at the departure of his people (Deuteronomy 32:13). But here he describes the extraordinary love of God toward the Church, when he says that he travels along with her, and undertakes to supply all her needs, as if he were consulting his own interests when he assisted his people.