Calvin begins his Institutes of the Christian Religion by showing how knowledge of God and knowledge of man are necessarily intertwined, in that the more we understand the holiness of God, the more we realize how great the offense of our sin is before Him; and the more we understand our sin, the more we realize how patient and merciful God is to us, and the more we understand the greatness of the work of our Lord Christ on our behalf.
Here’s a taste:
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 once begin to raise our thoughts to God, and reflect what kind of Being he is, and how absolute the perfection of that righteousness, and wisdom, and virtue, to which, as a standard, we are bound to be conformed, 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.
–Calvin, Institutes, 1.1.2.
If you ever hear someone with Reformed credentials talk about Calvin’s discussion of knowing God and knowing man being intertwined but make no reference to sin, you should smell a rat.