“You have often heard it said that when God formed man from a clod of earth, the devil also took earth and fashioned a toad or a monk from it. And this saying is also current, that where God builds a church, the devil places a chapel next door. The Christian Church is of two kinds. The word “church” is often a misnomer: people call that the Christian Church which is not the Christian Church, and that which is the Christian Church is often not acknowledged as such. It is not a question whether one must believe the church, or whether there is a church; but the issue is: Which is the true church? For we are agreed with the pope that there is a church. We believe that there assuredly is a Christian Church. The pope concurs in this. We are as firmly and strongly convinced as they that there must be a Christian Church on earth. But this is the question at issue and the bone of contention: Which is the Christian Church? For the devil and the pope dismember, pervert, and falsify all names.
The Anabaptists claim that they have Baptism, and that there is no salvation without it. No, we do not ask, or argue about, whether there is a saving Baptism. The same thing holds true of the Sacramentarians. We concede that they have the Sacrament of the Lord’s Supper. We agree on this. But the question in dispute is: Who has the true Sacrament? It is, of course, also incumbent on the Christian Church to preach the Gospel. But this suggests the question: Which is the true Gospel, and who possesses it in its purity? Similarly, we are now debating the question with the pope whether the papists or we are the true Christian Church, whether they have and administer Baptism, the Gospel, and the Lord’s Supper correctly. They claim to have these unalloyed. So do we” (Luther’s Works, v. 23, p. 285).