[M]an never attains to a true self-knowledge until he has previously contemplated the face of God, and come down after such contemplation to look into himself.
For (such is our innate pride) we always seem to ourselves just, and upright, and wise, and holy, until we are convinced, by clear evidence, of our injustice, vileness, folly, and impurity. Convinced, however, we are not, if we look to ourselves only, and not to the Lord also —He being the only standard by the application of which this conviction can be produced.
[S]ince we are all naturally prone to hypocrisy, any empty semblance of righteousness is quite enough to satisfy us instead of righteousness itself. And since nothing appears within us or around us that is not tainted with very great impurity, so long as we keep our mind within the confines of human pollution, anything which is in some small degree less defiled delights us as if it were most pure… So long as we do not look beyond the earth, we are quite pleased with our own righteousness, wisdom, and virtue; we address ourselves in the most flattering terms, and seem only less than demigods.
But should we . . . begin to raise our thoughts to God, and reflect what kind of Being he is . . . what formerly delighted us by its false show of righteousness will become polluted with the greatest iniquity; what strangely imposed upon us under the name of wisdom will disgust by its extreme folly; and what presented the appearance of virtuous energy will be condemned as the most miserable impotence. So far are those qualities in us, which seem most perfect, from corresponding to the divine purity.
Hence that dread and amazement with which as Scripture uniformly relates, holy men were struck and overwhelmed whenever they beheld the presence of God.
When we see those who previously stood firm and secure so quaking with terror, that the fear of death takes hold of them . . . [we see that] men are never duly touched and impressed with a conviction of their insignificance, until they have contrasted themselves with the majesty of God. Frequent examples of this consternation occur both in the Book of Judges and the Prophetical Writings; so much so, that it was a common expression among the people of God, “We shall die, for we have seen the Lord.”
Hence the Book of Job, also, in humbling men under a conviction of their folly, feebleness, and pollution, always derives its chief argument from descriptions of the Divine wisdom, virtue, and purity. Nor without cause: for we see Abraham the readier to acknowledge himself but dust and ashes the nearer he approaches to behold the glory of the Lord, and Elijah unable to wait with unveiled face for His approach; so dreadful is the sight…
[T]he knowledge of God and the knowledge of ourselves are bound together by a mutual tie, [but we must] treat of the former in the first place, and then descend to the latter.
John Calvin, The Institutes of the Christian Religion, 1.1.2-3