Both Eastern Orthodoxy and confessional Reformed theology affirm the ecumenical creeds and profess commitment to their doctrinal orthodoxy. Yet within that shared creedal framework, irreducible doctrinal differences emerge—most apparently in the Reformation doctrines of sola Scriptura and justification sola fide. By sola Scriptura, the Reformed confess that Holy Scripture, as the self-authenticating Word of God, stands as the supreme and final authority in all matters of faith and life, such that the Holy Spirit speaking in Scripture judges all councils, traditions, and human opinions (Westminster Confession of Faith 1.10). By justification sola fide, the Reformed confess that God justifies sinners by imputing to them the righteousness of Christ alone, received through faith alone, apart from the good works of the believer, in union with Christ (Shorter Catechism 33).

Without the clarity offered by these two doctrinal touchstones, one risks conflating fundamentally distinct doctrines under shared terminology and thereby obscuring differences decisive for both Scripture and salvation. Engagement with Eastern Orthodoxy can otherwise become mired in ambiguous categories such as “mystery,” “participation,” or “tradition.” Responsible comparison requires focusing on those topics where both traditions speak with doctrinal clarity.

Eastern Orthodoxy rejects the Reformed understanding of both sola Scriptura and justification sola fide. Orthodoxy locates Scriptural authority within the church’s infallible interpretive tradition; the Reformed locate it in the self-authenticating voice of the Spirit speaking in Scripture. Orthodoxy construes justification within transformative theosis[1]; the Reformed define justification as a forensic act grounded in Christ’s imputed righteousness and received by faith alone. These doctrinal differences are substantive, irreducible, and of great religious significance.

The Authority of Scripture and the Nature of Justification

I have chosen to frame Eastern Orthodoxy for the purpose of this introductory essay initially on The Confession of Dositheus (1672), given its historical and polemical function within the Orthodox world, particularly in its direct engagement with Reformed theology. The Confession arose from the Synod of Jerusalem (1672), convened in response to the perceived influence of Reformed teaching, especially in connection with the legacy of Cyril Lucaris. It aimed largely to repudiate Protestant doctrines and by contrast to confess the teaching of the Eastern Church at precisely those points under dispute. As such, it stands as a deliberate and self-conscious statement of Eastern Orthodoxy over against the Reformation.

While later Orthodox theologians—such as Vladimir Lossky, John Meyendorff, John Zizioulas, Kallistos Ware, and Andrew Louth—introduce refinements and nuances to Eastern Orthodox doctrine, their doctrine nevertheless coheres with the theological substance expressed in this Confession and bears its unmistakable impress. The Confession of Dositheus is not an ecumenical or universally binding conciliar standard within Eastern Orthodoxy.[2] It does not function as a final dogmatic norm in the same way as the Ecumenical Councils, as received within the infallible “Holy Tradition” of the Eastern church. Yet precisely because the Confession arises from a polemical engagement with Reformation theology, it proves especially useful for our present purpose. It gives formal, ecclesiastically sanctioned expression to how Eastern Orthodoxy understood and rejected the formal and material causes of the Reformation, namely sola Scriptura (Article 2) and justification sola fide (Article 13). While not exhaustive of the tradition, it provides a representative and clarifying witness at these principal points.

Scripture and Tradition

The divergence regarding the formal cause (sola Scriptura) emerges forcefully in The Confession of Dositheus. The church stands as the living, Spirit-taught organ of truth. Article 2 establishes the controlling premise: “The Holy Scriptures must be interpreted, not by private judgment, but in accordance with the tradition of the Catholic Church, which can not err, or deceive, or be deceived, and is of equal authority with the Scriptures.”[3] Scripture is received as authoritative, yet that authority is not self-evidencing as standing above the church; it is normatively determined within Holy Tradition.

Scripture is therefore known and received within the life of the church, yet it does not stand as a self-authenticating canon apart from ecclesial mediation. Leading Eastern theologian Kallistos Ware expresses this point with clarity:

The Bible is the supreme expression of God’s revelation to the human race and Christians must always be people of the book. But if Christians are people of the book, the book is the book of the people. It must not be regarded as something set up over the church but as something that lives and is understood within the church. That is why one should not separate scripture and tradition. It is from the church that the Bible ultimately derives its authority. For it was the church which originally decided which books form a part of holy scripture and it is the church alone which can interpret holy scripture with authority.[4]

In this formulation, Scripture’s authority is affirmed, but it is accessed and exercised through the Spirit-guided life of the church. As a result, the church functions not only as a witness to the authority of Scripture, but as the decisive context in which its meaning is interpreted and its authority is established. There is no room for the self-authenticating Word of God as the supreme authority by which the Holy Spirit, speaking in Scripture, judges all councils, traditions, and human opinions (WCF 1.10).

At this point, the deeper logic of the Orthodox emerges. The church’s role as the authoritative interpreter of Scripture does not rest merely on institutional continuity or historical succession, but on a theological claim about the nature of the church itself—its sacramental participation in the life of God. Its infallibility, as asserted in the Confession, traces in one way or another to its sacramental participation in the “energies” of God in union with Christ by the living power of the Spirit.[5] Precisely because the church is understood to share, by grace, in the divine life it proclaims, its doctrinal consciousness is regarded as Spirit-formed and therefore infallible. The same participatory union that effects transformation (theosis) is also said to secure right judgment in matters of faith (Holy Tradition), so that the church’s reception and interpretation of Scripture carries an authority commensurate with the life of God in which it participates. The church, as a community undergoing transformation and participation in divine life (theosis), becomes the authoritative locus in which revelation is rightly received and known.

Justification within Transformative Theosis

The divergence on the material cause in Article 13 follows the same principial pattern just surveyed. The Confession of Dositheus explicitly rejects justification by faith alone: “Man is justified, not by faith alone, but also by works.”[6] This affirmation strikes directly at the Reformation’s doctrine of justification sola fide. Moreover, Article 14 affirms that “only the works of the regenerate, done under grace and with grace, are perfect, and render the one who does them worthy of salvation.”[7]

The Confession expresses a synergistic and transformative account of justification. It declares that “the faith which is in us, justifies through works, with Christ.” Here faith does not justify as an instrument that receives righteousness from outside the sinner; rather, it justifies as it operates in conjunction with works. Works “worthy of salvation” prove intrinsic to justification itself. They are described as “fruits in themselves, through which faith becomes efficacious,” and even as “meriting, through the Divine promises.” Justification thus involves a proper synergism between divine grace and human response in which justifying righteousness is cultivated and embodied in the life of the believer.

At a still deeper level, salvation for the Eastern Orthodox means “to become god, to attain theosis, ‘deification’ or ‘divinization.’ For Orthodoxy our salvation and redemption mean our deification.”[8] Theosis involves two main aspects: “The ontological aspect concerns the transformation of human nature by incarnation, and the dynamic aspect concerns the appropriation of this deified humanity through the sacraments.”[9] Meyendorff argues that “the humanity of Christ, ‘enhypostasized’ by the Logos, is penetrated with divine energy, and Christ’s body becomes the source of divine light and deification. It is ‘theurgic,’ that is, it communicates divine life to those who are ‘in Christ’ and participate in the uncreated energies active in it.”[10] Theosis encompasses justification, shifting focus from imputed righteousness and forensic declaration as found in justification sola fide to participatory righteousness through union with Christ’s deified humanity. Justification in Eastern Orthodoxy is therefore a transformative participation in theosis effected through sacramental union with the deified humanity of Christ.

The contrast with the Reformation emerges clearly: The Reformed locate both biblical authority and forensic righteousness extra nos—in the self-authenticating Word of God and the imputed righteousness of Christ. Eastern Orthodoxy locates both in various ways within the life of the church and the transformative participation of the believer in theosis. These are systematic divergences that permeate and shape each tradition’s doctrinal conceptions.

The Doctrine of the Covenant of Works

Yet these doctrinal contrasts point to a still more fundamental theological issue. The Reformed have accounted for the self-authenticating authority of Scripture and the imputation of Christ’s righteousness by appealing to the basic category of the covenant of works. As summarized in WCF 7.1–2 and developed by theologians such as Francis Turretin, Geerhardus Vos, and Cornelius Van Til, Adam was created in the image of God (special creation) and immediately addressed by God in a covenantal Word from God (special providence). In his voluntary condescension, God’s Word to Adam bore an intrinsic, self-authenticating authority; it did not derive its authority from any external source but stood over Adam as the final standard of truth and obedience. By that same voluntary condescension, Adam was placed under the just terms of the covenant of works, obligated to render perfect obedience according to its prescribed conditions. That obedience, had it been rendered, would have been ex pacto meritorious, meeting the terms of covenantal justice, and would have been imputed to Adam’s natural posterity by virtue of his representative headship.

These two features inherent in the covenant of works stand in direct structural parallel to sola Scriptura and justification sola fide. Both authority and representation in the covenant of works inhere in the special revelation of voluntary condescension, thereby grounding a self-authenticating inscripturated Word (sola Scriptura) and the imputation of meritorious obedience (justification sola fide). Accordingly, the doctrine of the covenant of works supplies the internal theological rationale for both sola Scriptura and justification sola fide. In the covenant of grace, God’s inscripturated Word bears self-authenticating authority, and the righteousness of Christ is imputed to believers by faith alone in union with him.

The Religious Significance

By contrast, the Eastern doctrine of theosis would reject and restructure the entire religious edifice of Reformed theology. It blurs the Creator–creature distinction in theosis, forfeits the self-evidencing authority of Scripture as the supreme norm with its doctrine of Holy Tradition, and construes righteousness in terms of a synergistic participation in the divine energies. Accordingly, a right standing before God no longer rests solely on the finished, meritorious obedience of Christ imputed and received by faith alone, but is bound up with an ongoing process of cooperative deification.

This synergism entails a corresponding loss of assurance—consistent with the Eastern rejection of the perseverance of the saints—since the faithful may finally fall away. In The Orthodox Way, Kallistos Ware teaches that salvation depends on the “convergence” of divine grace and human cooperation, both “indispensable.” Yet he also affirms that, because human freedom endures, “so to all eternity it lies in man’s power to reject God.”[11] Taken together, these claims entail that salvation is not indefectibly secured and irresistibly applied but remains contingent upon ongoing cooperation with grace—a cooperation that can cease, and with it, participation in the life of God.

The Reformed doctrine of the covenant offers the remedy for such a perilous religious conception: “The covenant of grace has its fixity in God alone, who answers for both parties, and effects man’s willing and working by the Holy Spirit.”[12] Where God stands for both parties in Christ, assurance rests on a completed, unalterable work grounded in the Mediator in his estates of humiliation and exaltation. But where righteousness and beatitude depend upon human cooperation, that fixity is displaced, and with it the unassailable security Scripture ascribes to those justified by faith in union with Christ.

Eastern Orthodoxy, by grounding authority in Holy Tradition and righteousness in synergistic theosis, builds religious hope upon sand—unstable and contingent—whereas confessional Reformed theology builds religious hope upon the rock—the firm foundation of the covenant of grace, as the self-evidencing Scriptures authoritatively reveal a finished work and an imputed righteousness,
received by faith alone, as both righteousness and beatitude are infallibly secured by Christ and granted in union with Christ to the glory of God alone (soli Deo Gloria).

Endnotes

[1] In Eastern Orthodoxy, theosis is the baptized person’s transformative participation in the life of God by sacramental grace through union with Christ, whereby one becomes “by grace” what God is “by nature” yet mysteriously without sharing in the divine essence. Consult Kallistos (Timothy) Ware’s The Orthodox Church: An Introduction to Eastern Christianity, rev. ed. (Penguin Books, 1993), 226.

[2] The eighteen articles were published with some changes in a Russian version in 1838.

[3] Philip Schaff, The Creeds of Christendom, with a History and Critical Notes: The History of Creeds, vol. 1 (Harper & Brothers, 1878), 63. Schaff adds his own commentary: “Essentially Romish, but without an infallible, visible head of the Church.”

[4] Ware, The Orthodox Church, 193. For a contrasting Reformed account of how the church is formed by the canon, see M. G. Kline, The Structure of Biblical Authority, 2nd ed. (Eerdmans, 1975). 

[5] Ware, The Orthodox Church, 192, 231. The authority of Holy Tradition is rightly apprehended only from within the process of theosis, and it is precisely through that process that its truth is recognized, embodied, and transmitted.

[6] Schaff, Creeds, 64.

[7] Ibid. (emphasis added).

[8] Ware, The Orthodox Church, 225.

[9] Emil Bartos, Deification in Eastern Orthodox Theology (Paternoster, 1999), 10.

[10] John Meyendorff, “Introduction,” in Gregory Palamas: The Triads, ed. Richard J. Payne and John Meyendorff, trans. Nicholas Gendle, The Classics of Western Spirituality (Paulist Press, 1983), 19–20.

[11] Kallistos Ware, The Orthodox Way (St. Vladimir’s Orthodox Theological Seminary Press, 1979), 149–50, 181.

[12] Geerhardus Vos, Redemptive History and Biblical Interpretation: The Shorter Writings of Geerhardus Vos, ed. Richard B. Gaffin Jr. (P&R Publishing, 2001), 257.

The author is pastor of Trinity OPC in Easton, Pennsylvania, and fellow of biblical and systematic theology at Reformed Forum. New Horizons, June 2026.