When Augustine was contemplating becoming a Christian Simplicianus, Ambrose's tudor and assistant, told him a story about Victorinus. Victorinus was a Roman rhetorician and translator of neo-Platonic philosophical works. He had begun to read the Scriptures and study the Christian faith, encouraged by Simplicianus. Simplicianus told Augustine that Victorinus once came to him in private saying, "I should like you to know that I am now a Christian." Simplicianus replied, "That I will not believe, and I shall not count you as a Christian until I see you in the church of Christ." That was wise advice from Simplicianus to Augustine, the young man for whom contemplation was everything.
The Latin in the title to this post means "There is no salvation outside of the church." Typically, we add "ordinarily" to that slogan just to be sure that everyone understands that there are extraordinary situations where people do trust Jesus but are not able to join with a local congregation. The point is, however, that becoming a Christian is not simply something that happens in one's head.