Irenaeus: Gnostics Deny the Sufficiency of Scripture

Irenaeus (c. 130-c. 200) speaking of the Gnostics: When, however, they are confuted from the Scriptures, they turn round and accuse these same Scriptures, as if they were not correct, nor of authority, and [assert] that they are ambiguous, and that the truth cannot be extracted from them by those who are ignorant of tradition. For [they allege] that the truth was not delivered by means of written documents, but viva voce:

ANF: Vol. I, Against Heresies, Book 3:2:1.