The confession teaches that local churches can be more or less pure depending on how faithfully they adhere to correct doctrine and worship. Yet, it acknowledges that even the purest churches might contain some theological error, while other churches have become so corrupted that they can no longer be called churches of Christ but instead are of Satan. The confession affirms that only Jesus Christ can be head of the church. It states that the pope is an Antichrist who "exalteth himself, in the Church, against Christ and all that is called God."