19 But with respect to the refutation of custom which they seem to oppose to the truth, who is so foolish as to prefer custom to truth, or when he sees the light, not to forsake the darkness?— unless most ancient custom in any respect avail the Jews, upon the advent of Christ, that is, the Truth, in remaining in their old usage, and forsaking the new way of truth. And this indeed you Africans are able to say against Stephen, that when you knew the truth you forsook the error of custom.
But we join custom to truth, and to the Romans' custom we oppose custom, but the custom of truth; holding from the beginning that which was delivered by Christ and the apostles. Nor do we remember that this at any time began among us, since it has always been observed here, that we knew none but one Church of God, and accounted no baptism holy except that of the holy Church. Certainly, since some doubted about the baptism of those who, although they receive the new prophets, yet appear to recognise the same Father and Son with us; very many of us meeting together in Iconium very carefully examined the matter, and we decided that every baptism was altogether to be rejected which is arranged for without the Church.
Source: The Epistles of Cyprian (New Advent)