The faith of the Church is "one faith" (Eph.4: 5). The Church reminds us every day of this one faith, in a reading we pray in Matins from chapter four of Saint Paul's Epistle to the Ephesians. This one faith is the faith of every member of the Church. Whoever did not believe was isolated by the Church and forbidden to mix with others lest he corrupt their faith. Therefore, our teacher St. John the Evangelist says: "If anyone comes to you and does not bring this doctrine, do not receive him into your house nor greet him; for he who greets him shares in his evil deeds" (2John. 10, 11).