"God is our refuge and strength, an ever-present help in trouble. Therefore we will not fear, though the earth give way and the mountains fall into the heart of the sea, though its waters roar and foam and the mountains quake with their surging." (Psalm 46:1-3)
It was this beautiful Psalm that formed the basis of this Hymn by the reformer, Martin Luther, undoubtedly his most well-known. He composed the words and melody between 1527-1529.
It has been translated into many different languages including English at least seventy times.
A mighty Fortress is our God, A Bulwark never failing; Our Helper He amid the flood Of mortal ills prevailing: For still our ancient foe Doth seek to work us woe; His craft and power are great, And, armed with cruel hate, On earth is not his equal.
Further lyrics can be found here...