For Scripture is the school of the Holy Spirit, in which, as nothing is omitted that is both necessary and useful to know, so nothing is taught but what is expedient to know. Therefore we must guard against depriving believers of anything disclosed about predestination in Scripture, lest we seem either wickedly to defraud them of the blessing of their God or to accuse and scoff at the Holy Spirit for having published what it is in any way profitable to suppress.
John CalvinLet it stand, therefore, as an indubitable truth, which no engines can shake, that the mind of man is so entirely alienated from the righteousness of God that he cannot conceive, desire, or design any thing but what is wicked, distorted, foul, impure, and iniquitous; that his heart is so thoroughly envenomed by sin that it can breathe out nothing but corruption and rottenness; that if some men occasionally make a show of goodness, their mind is ever interwoven with hypocrisy and deceit, their soul inwardly bound with the fetters of wickedness.
John CalvinIn a way, the futile excuses many people use to cover their superstitions are demolished. They think it is enough to have some sort of religious fervor, however ridiculous, not realizing that true religion must be according to God's will as the perfect measure; that He can never deny Himself and is no mere spirit form to be changed around according to individual preference.
John CalvinScripture 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 Calvin