I am a keen admirer of Luther, and I am glad you throw the spotlight on his legacy with your series. Luther wrote this hymn at a time when the Black Plague loomed across Europe. He wrote it as a consolation to self and society, as many of his friends and friends of friends fell to their death from the terrible epidemic. Today, it will rings through and true as the truth that gives the bothered soul rest - that a mighty fortress is our God.