12:10-16 When the gospel should be publicly preached, the Gentiles would seek Christ Jesus as their Lord and Saviour, and find rest of soul. When God's time is come for the deliverance of his people, mountains of opposition shall become plains before him. God can soon turn gloomy days into glorious ones. And while we expect the Lord to gather his ancient people, and bring them home to his church, also to bring in the fulness of the Gentiles, when all will be united in holy love, let us tread the highway of holiness he has made for his redeemed. Let us wait for the mercy of our Lord Jesus Christ unto eternal life, looking to him to prepare our way through death, that river which separates this world from the eternal world.
Isa 12:1-6. Thanksgiving Hymn of the Restored and Converted Jews.
Just as Miriam, after the deliverance of the Red Sea (Isa 11:16), celebrated it with an ode of praise (Ex 15:1-19).