"The truth is self-authenticating and cannot be overthrown even if wickedness shamelessly opposes the precept of truth."
Source: Frank Williams, trans., The Panarion of Epiphanius of Salamis, Books II and III (Sects 47-80, De Fide), 66. Against Manichaeans, 10,4 (Leiden: E.J. Brill, 1994), p. 230.
For an excellent compilation of quotes of the Church fathers teaching on the primacy, sufficiency and ultimate authority of Scripture, get a copy of Holy Scripture:The Ground and Pillar of Our Faith Vol III- The Writings of the Church Fathers Affirming the Reformation Principle of Sola Scriptura.