Immediate belief is not blind persuasion; moral marks are helps, not de fide proofs
Next, when we say we believe Scripture immediately by the Spirit's inward efficacy, not by some proof stepping in between, we do not mean that our faith about sacred Scripture is a blind persuasion with no reason of its own.
Nor do we deny that the person who believes Scripture as he should is led there by arguments that can persuade a prudent mind that Scripture is true and comes from God.
By that word immediately we shut out only the proofs the schools call de fide — proofs drawn from some principle of faith, that make a matter of faith, and that can by themselves found an article of faith — not every kind of proof whatever.
The arguments that urge sacred Scripture's divinity are not of that kind. They are not taken from any principle or rule of faith, but only from various notes and signs, and they consist wholly of moral arguments that cannot of themselves yield the certainty faith requires — for the certainty owed to faith equals, if it does not surpass, every certainty demonstration can produce.
So although those proofs are helps to faith and motives for believing, the full certainty by which we ought to embrace the sacred books is not to be referred to them as its proper and chief foundation, but rather to the Spirit's inward persuasion.
Latin
IX. Deinde, quum dicimus nos immediate Scripturae credere, per internam Spiritus sancti efficaciam, non vero probationis alicujus interventu, sententia nostra non est, fidem nostram de Scriptura sacra esse caecam persuasionem, et quae sui nullam rationem habeat. Neque per id negamus, eum qui Scripturae, sicuti par est, credit, eo adduci quibusdam argumentis, quae viro prudenti suadere possunt Scripturam veram esse, et a Deo profectam. Etenim per vocem illam immediate non excludimus probationes qualescunque, sed solum probationes quas scholae vocant de fide, id est, quae petitae sint ex aliquo fidei principio, et faciant rem esse de fide, et possint per se fidei articulum fundare. Hujusmodi vero non sunt probationes illae quibus Scripturae sacrae divinitas suadetur. Nec enim petuntur ex ullo fidei principio, et ex aliqua fidei regula; sed tantum ex notis et signis variis: et totae constant argumentis quibusdam moralibus, quae per se parere non possunt eam certitudinem quae requiritur in fide: quandoquidem certitudo quae fidei debetur, ex se et ex suo genere, aequat, si non superat, certitudinem omnem quae nasci potest ex demonstratione. Ac proinde, quamvis probationes istae sint fidei adjumenta et credendi motiva, attamen plena fidei certitudo, qua libros sacros amplecti debemus, ad eas referenda non est, tanquam ad proprium atque praecipuum suum fundamentum, sed potius ad internam Spiritus sancti persuasionem.