" The Lutheran Church is actually not only “a” but “the” true visible Church of God on earth, insofar as “true” means nothing other than “as it should be according to the Word of God.” We neither can nor do we want to boast before other churches about our pious behavior. But we can and must boast about the pure doctrine which, by God’s grace to us poor sinners, shines among us like the clear bright light of the sun. "

― Matthew C. Harrison , Closed Communion? Admission to the Lord's Supper in Biblical Lutheran Perspective