But Jesus doesn't here mean just stand up during the assembly, and tell everyone the problem. He means take it to the Church authority, so that the erring brother can be corrected and then, if necessary, excommunicated. And if he is excommunicated, then he is not merely excommunicated from the local assembly, but from the entire institutional Church. Otherwise, he could just move to a different city and remain in full communion with the Church. The efficaciousness of church discipline in the local assembly presupposes that the Church is one universal institution. We see this also in Acts 15, at the Council of Jerusalem. All the local congregations were under the authority of the Apostles and Elders. As the Apostles died, the elders were made bishops, and continued leading this universal institution, meeting together in synods and to ordain other bishops. The idea that the Church is merely the "set of all believers" was unheard of until the 16th century. That should help us rightly interpret the passages in Scripture that speak of the Church.
-A8
Nice assumptions, extrapolations and inferences.
Not the only plausible ones but, no doubt comforting to the RC edifice to construe things that way.
A, your references to +Ignatius of Antioch certainly ought to settle the question of what the early Church believed The Church is, at least from an historical perspective. As you point out, the notion that there is some sort of “invisible” Church is simply unknown until the Protestant Reformation, again at least from an historical perspective. One will search the writings of the Fathers and the acts of the Councils in vain for anything like an invisible Church concept.
I suspect that the idea arose after the reformers broke with the Latin Church which, at least then (and even into my lifetime) and for about 5 centuries before that, was quite adamant that there was no salvation outside of the Latin Church; indeed it taught that there was no salvation absent submission to the universal immediate jurisdiction of the Pope. In the East one doesn’t see this idea as firmly and universally accepted. In other words, among the Orthodox and Oriental Orthodox there was not and is not any consensus that theosis/salvation is found only within the bounds of The Church. This is not to say that in the East we say that theosis is found outside The Church. We say simply that we know it is found within The Church, don’t know if it is found outside and can’t presume to limit the economy of salvation. For Orthodoxy, membership in The Church/theosis is not necessarily a closed system.
But the reformers were acting within the context of a Latin system and mindset which condemned to hell anyone who wasn’t “in” The Church, and the Latin Church at that. Since they were clearly not “in” and since being “in” was the sine qua non of salvation, they certainly had to come up with something and thus this idea of an invisible church came up. Apparently the reformers were as convinced as the Latins that membership in a “church”, if not The Church as the Latins would have it, was indeed necessary for salvation.
So the issue was and is where salvation is found. Where the reformers went off the rails, in my opinion, was in the thoroughly innovative idea of what constituted The Church. Interestingly, in the East, especially by the 7th century, but earlier too, one reads comments from members of The Church about bishops, priests, monks and laity who were members of hierarchial, ecclesial, eucharistic assemblies which were not part of The Church. These writers were quite clear that they did not accept that the eucharist, or any of the sacraments of these "ecclesial groups" was in any way valid or efficacious...but they never wrote that these people were ipso facto damned.
Bottom line, The Church, the Ecclesia, is a visible, hierarchial, Eucharistic institution within which we can be saved. There is no other "Church" or "church". To say otherwise is simply a 16th century innovation. To say with certitude however that theosis is NOT found outside the visible institution of the Ecclesia (let alone that it is only found in communion with the Pope of Rome) is simply itself outside the 2000 year old consensus patrum.