Demetrios Bathrellos has this to say about sin:
Sin must not be understood primarily in forensic terms, for instance as the transgression of divine law. It must be seen primarily in relational terms. Sin primarily consists in parting company with God. Likewise, salvation is the result of the re-establishment of this relationship.
Sin, therefore, implies a broken relationship with God. But this brokenness goes far deeper than its external manifestations in human action. Human sinfulness consists first of all in a deep ontological, existential and structural deformation and depravity of man’s very being. It is this deep, existential and ontological captivity to sin that is subsequently expressed in sinful activity. Sinful activity, in turn, reinforces human depravity and alienation from God. (Paul Metzger, ed.,”Trinitarian Soundings in Systematic Theology: Demetrios Bathrellos, “Chpt. 9: The Sinlessness of Jesus: A Theological Exploration in the Light of Trinitarian Theology,” 114-115)
And in line with this definition of sin, Ron Frost has this to say as corollary:
The essence of sin, then, is a privation of relationship rather than a particular behaviour or even a breach of covenant between ‘individuals’ in the fashion of a self-concerned Cartesian contract. It is, instead, to reject God’s love as revealed in Christ and as witnessed by the Spirit. Luther concluded ‘that this is the sin of the world that it does not believe on Christ. Not that there is no sin against the law besides this; but that this is the real chief sin, which condemns the whole world even if it could be charged with no other sin.’ (Paul Metzger, ed., “Trinitarian Soundings in Systematic Theology,” Ron Frost, “Chpt. 8: Sin and Grace,” 107)
Both of these accounts of sin are shaped by the presupposition that sin is primarily a relational problem, which is to say that any other framing of sin — such as the Calvinist Covenant of Works provides — “misses the mark.” Here is how the Westminster Confession of Faith – chapt. XIX describes the Law of God and Covenant of Works:
I. God gave to Adam a law, as a covenant of works, by which He bound him and all his posterity, to personal, entire, exact, and perpetual obedience, promised life upon the fulfilling, and threatened death upon the breach of it, and endued him with power and ability to keep it.
II. This law, after his fall, continued to be a perfect rule of righteousness; and, as such, was delivered by God upon Mount Sinai, in ten commandments, and written in two tables: the first four commandments containing our duty towards God; and the other six, our duty to man.
III. Besides this law, commonly called moral, God was pleased to give to the people of Israel, as a church under age, ceremonial laws, containing several typical ordinances, partly of worship, prefiguring Christ, His graces, actions, sufferings, and benefits; and partly, holding forth divers instructions of moral duties. All which ceremonial laws are now abrogated, under the New Testament.
IV. To them also, as a body politic, He gave sundry judicial laws, which expired together with the State of that people; not obliging under any now, further than the general equity thereof may require.
V. The moral law does forever bind all, as well justified persons as others, to the obedience thereof; and that, not only in regard of the matter contained in it, but also in respect of the authority of God the Creator, who gave it. Neither does Christ, in the Gospel, any way dissolve, but much strengthen this obligation.
VI. Although true believers be not under the law, as a covenant of works, to be thereby justified, or condemned; yet is it of great use to them, as well as to others; in that, as a rule of life informing them of the will of God, and their duty, it directs and binds them to walk accordingly; discovering also the sinful pollutions of their nature, hearts and lives; so as, examining themselves thereby, they may come to further conviction of, humiliation for, and hatred against sin, together with a clearer sight of the need they have of Christ, and the perfection of His obedience. It is likewise of use to the regenerate, to restrain their corruptions, in that it forbids sin: and the threatenings of it serve to show what even their sins deserve; and what afflictions, in this life, they may expect for them, although freed from the curse thereof threatened in the law. The promises of it, in like manner, show them God’s approbation of obedience,and what blessings they may expect upon the performance thereof: although not as due to them by the law as a covenant of works. So as, a man’s doing good, and refraining from evil, because the law encourages to the one and deters from the other, is no evidence of his being under the law: and not under grace.
VII. Neither are the forementioned uses of the law contrary to the grace of the Gospel, but do sweetly comply with it; the Spirit of Christ subduing and enabling the will of man to do that freely, and cheerfully, which the will of God, revealed in the law, requires to be done.
You might read this and wonder what I am trying to get at; well let me try and clarify. The historically understood Calvinist understanding of the Law holds that sin is “Law-breaking;” and thus our only hope for salvation is that someone else (Jesus) comes and keeps the Law in our stead, and the imputed righteousness that we receive (see Romans) is based upon Christ’s active obedience to the moral constraints laid out in the Mosaic Covenant (or simply the “Law of God”) — this is called the Covenant of Grace (by the classically ‘Reformed’). In this framework, sin is understood to be “Law-breaking;” do you notice what this implies relative to the two previous definitions (Bathrellos and Frost) of sin and their relational framing? What this implies is that sin is not primarily a relational problem, but instead it is an external-behaviorial problem. This is why the “Westminster-Calvinists” place so much emphasis on “doing good works,” amongst the “elect.” From the “WC” perspective, if we (the “elect”) are in genuine union with Christ; and we have been given (imputed) His “Law-shaped-righteousness;” then we will evidence our union with Christ by “keeping the moral constraints of the Law.”
The real critique to me though, is simply derived from how sin is disparately framed in these two competing accounts (the relational vs. the “Law”); and thus what this implies about sin in the first place. That is, is sin an absence of God’s life in humanity; or is it “Law-breaking?” If the former then this is going to imply that sin is primarily a “heart” problem (internal); if the latter, then sin is “primarily” a “behavior” problem (external). And given the grace-sin symmetry how sin is ultimately dealt with will be shaped by what framework we approach this with. If the former, then we are going to approach this problem Trinitarianly; if the latter we will approach this issue Monadically (viz. through “classical theistic” lenses on how we think about God — i.e. primarily as the “Law-Giver”).
The real problem, and the reason why we ever have these two distinct approaches can really be reduced to a Theology Proper (how we conceive of God, and what philosophical assumptions we bring to understanding and articulating Him) issue. If we are going to understand sin as primarily a “relational problem,” then we are going to be, first, thinking of God in “relational/trinitarian terms.” If we are going to understand sin as primarily a “behaviorial problem,” then we have first understood God in terms that do not emphasize His relationality; but instead those that emphasize His “oneness of purpose” (or “Law-Giving” and man’s “Law-Keeping” or “Breaking”).
There is more to try and develop, of course, but I will have to leave this here. I will be attempting to develop this further by way of posts, and also by responding to any feedback in the comment meta — so feedback away ;-) !