You are wont, indeed, to bring up against us the letters of Cyprian, his opinion, his Council; why do ye claim the authority of Cyprian for your schism, and reject his example when it makes for the peace of the Church? But who can fail to be aware that the sacred canon of Scripture, both of the Old and New Testament, is confined within its own limits, and that it stands so absolutely in a superior position to all later letters of the bishops, that about it we can hold no manner of doubt or disputation whether what is confessedly contained in it is right and true….

Augustine, On Baptism Against the Donatists II.3–4. (HT: Adiaphora).