Aroused consciences, when they have to do with God, feel this [free justification in Christ alone] to be the only asylum in which they can breathe safely. For if the stars which shine most brightly by night lose their brightness on the appearance of the sun, what do we think will be the case with the highest purity of man when contrasted with the purity of God? For the scrutiny will be most strict, penetrating to the most hidden thoughts of the heart. As Paul says, it “will bring to light the hidden things of darkness and will make manifest the counsels of the heart,” (1 Cor. 4:5); will compel the reluctant and dissembling conscience to bring forward everything, even things which have now escaped our memory. The devil, aware of all the iniquities which he has induced us to perpetrate, will appear as accuser; the external show of good works, the only thing now considered, will then be of no avail; the only thing demanded will be the true intent of the will. Hence hypocrisy, not only that by which a man, though consciously guilty before God, affects to make an ostentatious display before man, but that by which each imposes upon himself before God (so prone are we to soothe and flatter ourselves), will fall confounded, how much soever it may now swell with pride and presumption. Those who do not turn their thoughts to this scene may be able for the moment calmly and complacently to rear up a righteousness for themselves; but this the judgment of God will immediately overthrow, just as great wealth amassed in a dream vanishes the moment we awake. Those who, as in the presence of God, inquire seriously into the true standard of righteousness, will certainly find that all the works of men, if estimated by their own worth, are nothing but vileness and pollution, that what is commonly deemed justice is with God mere iniquity; what is deemed integrity is pollution; what deemed glory is ignominy.

John Calvin, Institutes of the Christian Religion, 3.12.4