Karl Barth was fascinated with John Calvin, and he called Calvin a "demonic power" but also in the same breath, Barth said he could "spend all the rest of my life just with Calvin." Barth was fixated with John Calvin, so it is a perrennial desire of mine to reappropriate Calvin for good, and not for evil (unlike some Calvinists do today), and so I attempt to return to Calvin's original writings, ad fontes, to understand him in a new and better light! Karl Barth is occasionally dismissed for doing "dialectical theology", as if that was a bad thing! (I defer to Bruce McCormmack's Karl Barth's Critically Realistic Dialectical Theology to determine whether Barth's hermeneutical method was precisely "dialectical theology" or not.) Ironically, John Calvin himself may be described as a dialectical theologian!
John Calvin describes his hermeneutical method in the opening paragraph of his magnus opus, the Institutes of the Christian Religion in the vernacular of dialectic theology. Calvin says he doesn't know which comes first, the knowledge of God or the knowledge of ourselves: if we begin with the knowledge of ourselves, we become immediately aware of God, and if we begin with God, we become knowledgable of ourselves. So there is no clear and certain starting point in either God or ourselves, we are in tension between these two truths that are united dialectically. It is like looking at the sky, and realizing how small and grounded we are in the world. It is like looking at the ground and realizing how low we are beneath the vast heavens above us. Cyclically, as we look up, we look down, and as we look down, we look up. And as we look down, we become aware of the rest of creation, around us, that is in the same cycle, showing our solidarity with the earth, and how there is a God in heaven, yet we are here on earth. Therefore, I believe that John Calvin's theology is rightly described as "dialectical theology" based on this prolegomena paragraph.
John Calvin's opening paragraph is Calvin's prolegomena to his systematic theology. And all Reformed Dogmatics (or Systematic Theology) that followed Calvin, began with similar introductions that explained their hermeneutical methods. So the following quotation from Calvin's opening words to the Institutes of the Christian Religion cannot be dismissed as spurious, but may be understood as the cornerstone defining Calvin's theological method, and "dialectical theology" aptly describes it!
Here are the opening words of John Calvin's Institutes of the Christian Religion (translated by Battles). I encourage you to read the rest of the chapter to see how Calvin explains this initial words:
Nearly all the wisdom we possess, that is to say, true and sound wisdom, consists of two parts: the knowledge of God and of ourselves. But, while joined by many bonds, which one precedes and brings forth the other is not easy to discern. In the first place, no one can look upon himself without immediately turning his thoughts to the contemplation of God, in whom he "lives and moves" [Acts 17:28]. For, quite clearly, the mighty gifts with which we are endowed are hardly from ourselves; indeed, our very being is nothing but subsistence in the one God. Then, by these benefits shed like dew from heaven upon us, we are led as by rivulets to the spring itself. Indeed, our very poverty better discloses the infinitude of benefits reposing in God. The miserable ruin, into which the rebellion of the first man cast us, especially compels us to look upward. Thus, not only will we, in fasting and hungering, seek thence what we lack; but, in being aroused by fear, we shall learn humility. For, as a veritable world of miseries is to be found in mankind, and we are thereby despoiled of divine raiment, our shameful nakedness exposes a teeming horde of infamies. Each of us must, then, be so stung by the consciousness of his own unhappiness as to attain at least some knowledge of God. Thus, from the feeling of our own ignorance, vanity, poverty, infirmity, and—what is more—depravity and corruption, we recognize that the true light of wisdom, sound virtue, full abundance of every good, and purity of righteousness rest in the Lord alone. To this extent we are prompted by our own ills to contemplate the good things of God; and we cannot seriously aspire to him before we begin to become displeased with ourselves. For what man in all the world would not gladly remain as he is—what man does not remain as he is—so long as he does not know himself, that is, while content with his own gifts, and either ignorant or unmindful of his own misery? Accordingly, the knowledge of ourselves not only arouses us to seek God, but also, as it were, leads us by the hand to find him.
John Calvin, Institutes I.i.1 
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[^1] Calvin, John. Institutes of the Christian Religion. Ed. John T. McNeill. Trans. Ford Lewis. Battles. Philadelphia, PA: Westminster, 1960. 70. Print.
Related: dialectic, dialectical theology, Institutes, institutes of the christian religion, John Calvin, Karl Barth, prolegomena