Isaiah 26:1
1In that day, this song will be sung in the land of Judah: “We have a strong city. God appoints salvation for walls and bulwarks.
Wesley: In that day—when God shall do such glorious works, as are described in the foregoing chapter. Sung—in the church of God. A city—Jerusalem, or the church, which is often compared to a city. For walls—God’s immediate and saving protection shall be to his church instead of walls. A strong city; salvation as walls.
Judah’s song after Moab’s dust. Gospel church as city.
Calvin: in that day shall this song be sung in the land of Judah. After the return from captivity they will be defended by God’s power; Jerusalem as safe as if surrounded by bulwarks. The song was composed before the calamity, that they might not despair in captivity, when they were like dead men (Ezekiel 37). We have a strong city; salvation will God appoint for walls and bulwarks.
The walls are still salvation, not stone. The song is sung in Judah.