Scripture will ultimately suffice for a saving knowledge of God only when its certainty is founded upon the inward persuasion of the Holy Spirit. Indeed, these human testimonies which exist to confirm it will not be vain if, as secondary aids to our feebleness, they follow that chief and highest testimony. But those who wish to prove to unbelievers that Scripture is the Word of God are acting foolishly, for only by faith can this be known.
John CalvinWe say, then, that Scripture clearly proves this much, that God by his eternal and immutable counsel determined once for all those whom it was his pleasure one day to admit to salvation, and those whom, on the other hand, it was his pleasure to doom to destruction. We maintain that this counsel, as regards the elect, is founded on his free mercy, without any respect to human worth, while those whom he dooms to destruction are excluded from access to life by a just and blameless, but at the same time incomprehensible judgment
John Calvin