One of the most important controversies of the first generation of the Church was that of the relation between Gentile converts and Judaism. Did the Gentiles who believed in Christ have to be circumcised and take up the Law of Moses, or not? The apostles and the majority of the early Church came to the conclusion that such a thing was not necessary. Among the arguments they gave for this conclusion, one stands out.
The argument goes like this. Christ is the one who gives the Holy Spirit (Acts 2:33). The Gentiles received the Holy Spirit while they were still Gentiles, apart from being circumcised or obeying the Law (Acts 10:44). Thus, it makes no difference to one’s belonging to Christ and to the Father whether one is a Jew or a Gentile (Acts 15:7–9).
Paul gives this argument to the Galatians, as well: “The only thing I want to learn from you is this: Did you receive the Spirit by doing the works of the law or by believing what you heard? Are you so foolish? Having started with the Spirit, are you now ending with the flesh?” (Galatians 3:2–3) The apostolic argument implies that if a person has the Holy Spirit, there is nothing more to be done in order to be right with God. That person has been accepted by God and grafted into Christ.
This argument applies equally in the present day. There are a multiplicity of churches, but in each of them one finds people who believe in the Gospel of Christ, who call out to God as to their Father (cf. Gal 4:6), who live in righteousness and put to death the deeds of the flesh (cf. Rom 8). If we follow the apostolic logic, then it follows that belonging to any one of these particular churches is not necessary.