While believers were agreed among themselves and the body was one, it had no need to declare itself as a church. It was only when believers were split up into opposing parties, renouncing one another, that it seemed necessary to each party to confirm their own truth by ascribing to themselves infallibility. The conception of one church only arose when there were two sides divided and disputing, who each called the other side heresy, and recognized their own side only as the infallible church.
If we knew that there was a church which decided in the year 51 to receive the uncircumcised, it is only so because there was another church--of the Judaists--who decided to keep the uncircumcised out.
If there is a Catholic Church now which asserts its own infallibility, that is only because there are churches--Greco-Russian, Old Orthodox, and Lutheran--each asserting its own infallibility and denying that of all other churches. So that the one Church is only a fantastic imagination which has not the least trace of reality about it.
As a real historical fact there has existed, and still exist, several bodies of men, each asserting that it is the one Church, founded by Christ, and that all the others who call themselves churches are only sects and heresies.
The catechisms of the churches of the most world-wide influence--the Catholic, the Old Orthodox, and the Lutheran--openly assert this.
In the Catholic catechism it is said: "Quels sont ceux qui sont hors de l'église? Les infidèles, les hérétiques, les schismatiques."[4] The so-called Greek Orthodox are regarded as schismatics, the Lutherans as heretics; so that according to the Catholic catechism the only people in the Church are Catholics.
[4] "Who are those who are outside the Church? Infidels, heretics, and schismatics."
In the so-called Orthodox catechism it is said: By the one Christian Church is understood the Orthodox, which remains fully in accord with the Universal Church. As for the Roman Church and other sects (the Lutherans and the rest they do not even dignify by the name of church), they cannot be included in the one true Church, since they have themselves separated from it.
According to this definition the Catholics and Lutherans are outside the Church, and there are only Orthodox in the Church.