As an instructional document of Christian doctrine that has become “acknowledged as a symbolical book of the Reformed churches,” The Heidelberg Catechism espouses a uniform rule of Christian faith, from which the reformed movement in the Christian Church could be systematically voiced. What is voiced, undoubtedly, by the authors of The Heidelberg Catechism, is a concerted truth about Christianity, a means of structuring what it means to be a Christian in the reformed era, and an underlying supposition that, as an extrapolation of the reformed movement, it “clearly set[s] forth the true Christian doctrine.”
If The Heidelberg Catechism represents an organized articulation of a “true Christian doctrine,” then it, more specifically, assumes the functionality of catechization, which is a “brief and elementary instruction [that] is given by word of mouth in relation to the rudiments of the [Christian doctrine, in order to] signif[y] a system of instruction relating to the first principles of the Christian religion [as] designed for the ignorant and unlearned.” With the “ignorant and unlearned” in mind as the audience of this text, the authors utilize an interactive, question-and-answer format, where The Heidelberg Catechism embodies a specific method and language that is “well chosen [for anyone who generally might] desire the knowledge of the truth, [so that] they may live by it.” In this respect, then, for a Christian to live a distinctly Christian life of faith in reference to a theological desire to know the truth of a true Christian doctrine –albeit, to acknowledge a true Christian doctrine as the existential reference point for any Christian –there, first, should be a theologically most adequate understanding of sin.
In addition to certain inextricably-linked understandings that can be derived from the gospel, or salvation, and how God’s grace and human faith are related, the concept of sin is the impetus behind the concept of humanity as much as it is the theological starting point for developing a definition of what it means to be human. What this means is that, if the concept of sin is, as aforementioned, an existential reference point for a Christian, then, if being a Christian invokes a state of being, sinfulness must also be a state of being, an alternate one. Though, in the Christian tradition, the source of sin “is held to be hybris or pride, and concupiscence or lust [as being] attitudes [that] are interpreted as stemming from the failure to recognize the divine authority,” as an alternate state of being, there remains “the central idea that sin is a state of our being that separates us from the holy God.” Not only does sin, as a separation from God through separating the holy and the secular, incorporate a state of being in which God is not at the center but at the periphery, but it presents the possibility for alienation.
 George W. Bethune, Expository Lectures on the Heidelberg Catechism (New York, NY: Sheldon and Company, 1864), 10.
 The two authors were: Zacharias Ursinus, a learned professor at Heidelberg, and Casparus Olevianus, a court preacher, a favorite of Frederic III of Germany. Both Ursinus and Olevianus took part in the composition of the book, where Olevianus arranged his part as a simple illustration of the covenant of grace and Ursinus prepared two forms of a catechism: one of children in the schools and another suited for the more advanced. Though the labors of both Ursinus and Olevianus, ultimately, play equally important roles in the overall production of the Heidelberg Catechism, the system of the book must be attributed mainly to Ursinus. Ibid., 7.
 Ibid, 6.
 G. W. Williard, ed. The Commentary of Dr. Zacharias Ursinus on the Heidelberg Catechism (Cincinnati, OH: Elm Street Printing Company, 1888), 11.
 George W. Bethune, Expository Lectures on the Heidelberg Catechism (New York, NY: Sheldon and Company, 1864), 3.
 In using the term “existential,” what is being addressed is the concept of “being Christian” as equating to an understanding, an interpretation, and a perception of what is means to exist, in the most fundamental way, as a Christian. This, more importantly, presumes that “being Christian” personifies a certain state of being.
 The concepts of sin, salvation, and God’s grace are linked not just theologically by way of their interrelationships and inter-dependence, but, more poignantly, with the Christological assertion of Jesus Christ being the conduit for salvation from sin through the utilization of God’s grace-giving, divine power.
 To say that sin is an “alternate” state of being is to be in conflict with the Augustine-based view of sin as non-being due to assertion that sin has no reality and that it is a lack of perfect realization; this logic pertains the belief that sin has no positive ontological standing, where the term “non-being,” as applied to sin, refers to resistance against being and perversion of being. Paul Tillich, Systematic Theology: Volume I (Chicago, IL: The University of Chicago Press, 1951), 188.
 William L. Reese, Dictionary of Philosophy and Religion: Eastern and Western Thought (Atlantic Highlands, NJ: Humanities Press Inc., 1980), 530.
 Sinclair B. Ferguson and David F. Wright, eds., New Dictionary of Theology (Downers Grove, IL: InterVarsity Press, 1988), 641.
 The act of separation from God can also be viewed as the resistance to reunion with God. Since the act of forgiving for sins focuses on the particular sin as the symbol of forgiveness, the human mind concentrates on that particular sin and the moral quality of that sin rather than on the underlying estrangement from God and its religious quality. Paul Tillich, Systematic Theology: Volume III: Life and the Spirit History and the Kingdom of God (Chicago, IL: The University of Chicago Press, 1963), 225.
 Paul Tillich, Systematic Theology: Volume I (Chicago, IL: The University of Chicago Press, 1951), 218.