Isaiah 26:1

In that day, at the time of the final deliverance of the ransomed of God, shall this song be sung in the land of Judah, by the believers who have been preserved by the power of the Lord: We have a strong city, namely, the city of God, Psalms 46:4, His holy Church; salvation will God appoint for walls and bulwarks, His redemption is established as a strong wall of exterior and interior defense, so that no enemy is able to penetrate inside and take away the blessings of the redeemed.