Posted March 20, 2019
The identifying mark of the false church is that she lacks the marks of the true church, i.e., the pure doctrine of holy scripture, a pure administration of the sacraments; and the exercise of church discipline in the correcting of sin. Rich in the incidentals of size, ecclesiastical reputation, earthly influence, religious ritual and busyness, and pomp (which, alas, fascinate many professing Christians in every age); she is destitute of the essentials of the body of Jesus Christ in the world.
Still, she makes something of preaching, sacraments, and discipline. What she makes of them gives her away. She preaches another gospel than the gospel of salvation from sin by grace alone. She corrupts the administration of the sacraments by adding to the sacraments ordained by Christ, both as regards number and ritual; by taking away from the administration elements prescribed by Christ; by administering them to persons whom Christ judges unworthy; and, not least, by corrupting the meaning and truth of the sacraments in her teaching. She perverts the key power of discipline, for not only does she refuse to excommunicate those who live impenitently in grossest disobedience to the Law of God, but she also turns in fury upon those who, in their zeal for holiness, rebuke her for her wicked doctrines and evil practices. In short, she is not founded on, subject to, or upholding the truth of God's word, sacred scripture. Not submitting, thus, to the yoke of Christ, she is not Christ's bride, but a whore.
Since every believer knows the word of God, it is easy for him to know and distinguish the false church from the true church.
It is a mistake to identify one particular institute as the true church in distinction from all others which are then regarded as false. This is the position of Rome. Rome is the true church; all other churches are false. There might seem to be a softening of this hard line today. Rome calls the Protestants "separated brothers." The Second Vatican Council went so far as to refer to Protestant congregations as "Churches or ecclesial communities" and to say that "in some real way they are joined with us in the Holy Spirit" ("Dogmatic Constitution on the Church," Chapter II, 15). But Vatican II also insisted that Rome is "the Church," "Mother Church," and made clear that the "separated brothers" (read: "prodigal sons"!) must return to Rome.