Irenaeus argues that, to know what is true Christian doctrine, it is enough to learn the teaching of some of the oldest churches or at least one, in particular that of Rome: "If the apostles had known hidden mysteries, which they were in the habit of imparting to 'the perfect' apart and privily from the rest, they would have delivered them especially to those to whom they were also committing the Churches themselves. [...] Suppose there arise a dispute relative to some important question among us, should we not have recourse to the most ancient Churches with which the apostles held constant intercourse, and learn from them what is certain and clear in regard to the present question?"