False pretended principles fall by missing the Spirit's marks — not by proof-texts
Scripture's perfection does not require that it prove itself. Neither must every false pretended principle of faith be rejected by direct, express proof-texts.
We believe true faith principles immediately through the Spirit's inward illumination and persuasion. He sweetly draws people to them — not by another faith principle, but by motives and marks that make their divinity known.
So to refuse what are falsely counted as faith principles, it is enough that they lack the true marks of true principles, and that traces of human ignorance and weakness show in them.
Latin
XXI. Sicut autem ad perfectionem, quam Scripturae sacrae tribuimus, non requiritur, ut seipsam probet, ita quoque nihil necesse est, ut, quae falso obtenduntur fidei principia, per Scripturam directe & expresse rejici possint, atque ad hoc exigantur Scripturae testimonia. Sed quemadmodum veris fidei principiis immediate credimus, per illuminationem & persuasionem internam Spiritus sancti, qui homines eo suaviter adducit, non per aliud quoddam fidei principium, sed tantum motivis & notis quibusdam quibus divinitas eorum innotescit: sic ad rejicienda & non admittenda quae falso putantur fidei principia sufficit ut destituantur veris verorum principiorum notis, & in iis notari possint ignorantiae & imbecillitatis humanae vestigia.