"Then after fourteen years I went up again to Jerusalem with Barnabas, taking Titus along with me. I went up by revelation; and I laid before them (but privately before those who were of repute) the gospel which I preach among the Gentiles, lest somehow I should be running or had run in vain" (Gal. 2:1-2).Do we know of any organized Christian church that has not moved in the same direction as the Catholics did? Someone came of her, but usually [always?] the new group that often started on a good pathway found itself very close to the old mother church. Do we not meet people today who attend no physical assembly because they have so often found it to be more of the same-o same-o? Undoubtedly some may have found exceptions, but usually [always?] they are temporary exceptions that once given a death or two among the older more serious believers end up in another boat going the same mistaken direction.
Despite Paul's reception of a marvelous supernatural manifestation of Jesus Christ, he still feels the need to go up to Jerusalem to confer with the Apostles on the doctrine he is preaching. This suggests that the apostolic hierarchy is functioning as a sort of "gatekeeper" over what is "authentic" Christian doctrine; incidentally, this is the same idea that presupposes the calling of the Council of Jerusalem for the Apostles and bishops to solve the problem posed by Gentiles and the law. Protestants will most likely admit as much, but where they will fall short is in admitting that not only the Apostles but their successors continued to exercise this function, in which case we are talking about a permanent hierarchy, and hence an institution. As we shall see when we get to the letters of St. John the Apostle, this function of the hierarchy as "gatekeepers" of doctrine and discipline is still intact long after the original generation of Apostles had died. Paul's words to Timothy in 2 Tim. 2:1-2, examined below, are also relevant here.
"There is one body and one Spirit, just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of us all, who is above all and through all and in all" (Eph. 4:4-6).
Here Paul compares the oneness of the Church with the oneness of God, and says that there similarly must be only one faith and one baptism; how ironic, because the role of faith and the nature of baptism in particular are two extremely contentious points in Protestant theology. A loose communion of churches which bitterly disagree on the nature of faith and baptism, among others, cannot be the "one Body" with "one faith" and "one baptism" spoken of by Paul. And why do these Protestant sects disagree? Is it not because they are physically diverse communities with no formal unity? Formal disunity begets doctrinal disunity; conversely, the doctrinal unity that Paul teaches presupposes a formal, physical unity that goes beyond an invisible confederation of different groups. This is also the most commonly cited text in patristic writings when the unity of the Church is stressed.
The invisible Church of Luther is neither biblical nor historical.