Scripture is better known among the faithful than the Church herself
Their error is answered from this: among believers Scripture is better known than the Church herself.
Every Christian body agrees, at least on the chief books, which writings are true Scripture. Greeks, Armenians, Ethiopians, Pontificii, Protestants, and whatever other Christian parties remain today all acknowledge as Canonical the books our churches hold Canonical. Rome adds certain Old Testament books to its Canon; on the books we count Canonical it still agrees with us.
Those who denied or despised Scripture outright — as the Libertines are remembered to have done in our fathers' day — were few, obscure, and soon gone. Which Church is the true one is not settled the same way: each party claims to be it. The Greek, Armenian, and Ethiopian churches neither take Rome for God's true Church nor bind themselves to its authority.
Latin
XXVII. Inde vero error illorum refellitur quod Scriptura est aliquid apud fideles notius quam sit ipsa Ecclesia. Et hoc quia inter omnes Christianos constat quae sint verae Scripturae, saltem quoad partes praecipuas, ut patet per inductionem. Etenim Graeci, Armeni, Aethiopes, Pontificii, Protestantes, et si quae sint adhuc hodie Christianorum sectae, communi consensu agnoscunt libros, quos Ecclesiae nostrae pro Canonicis habent, revera Canonicos esse. Addunt quidem Pontificii quosdam alios libros ad Canonem veteris Testamenti: sed de illis quos Canonicos censemus nobiscum consentiunt. Quod si qui Scripturas in totum negarunt, vel contempserunt, quod patrum nostrorum memoria putantur fecisse Libertini, paucissimi fuerunt, nec ullius nominis, et cito defierunt. At non constat quae sit vera Ecclesia: sed unaquaeque secta pertendit se esse veram Ecclesiam. Nec Ecclesiae Graecae, Armeniacae et Aethiopicae Romanam Ecclesiam pro vera Dei Ecclesia habent, aut illius authoritate ullo modo se obstringi putant.