Theosis, Sanctification, Glorification

The Diversity

The three great branches of the Christian tradition describe the believer’s transformation into the likeness of Christ using different vocabularies — and the vocabularies carry different theological weight.

The Eastern Orthodox tradition speaks of theosis (theopoiesis, divinization): the human person participates in the divine nature, becoming by grace what God is by nature. This is not metaphor. Athanasius’s dictum is the locus classicus: “He became man that we might become god” (De Incarnatione 54.3, c. 335). Gregory Palamas’s distinction between the divine essence (forever inaccessible) and the divine energies (genuinely communicated to the creature) provides the ontological framework. Theosis is the telos of creation, the purpose for which humanity was made.

The Roman Catholic tradition speaks of sanctification through sacramental grace, culminating in the beatific vision. The creature is transformed by infused grace — the theological virtues (faith, hope, charity) are divinely implanted, and the sacramental life sustains and deepens them. The ultimate end is the visio Dei, the direct vision of God’s essence promised to the blessed in glory (1 John 3:2). Aquinas teaches that this vision requires the lumen gloriae, a created light that elevates the intellect to see what nature alone could never perceive (Summa Theologiae I, q.12, a.5).

The Protestant tradition speaks of progressive sanctification — the Holy Spirit’s ongoing work of conforming the believer to Christ’s image — and glorification at the resurrection, when the work is completed. The emphasis falls on the Spirit’s agency, the Word’s instrumentality, and the eschatological horizon: what we shall be has not yet appeared (1 John 3:2). Protestant usage of “sanctification” sometimes lacks the ontological density of the Eastern and Catholic frameworks, but its best exponents (Jonathan Edwards, the Wesleys) press toward a robust account of real transformation.

Scriptural Warrant for Each Position

For theosis: “He has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature” (2 Peter 1:4). This is the single most important text, and the East reads it with maximal ontological seriousness. Additionally: “I said, ‘You are gods’” (Psalm 82:6, cited by Christ in John 10:34); “we shall be like him, because we shall see him as he is” (1 John 3:2); “we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image from one degree of glory to another” (2 Corinthians 3:18).

For sanctification through grace: Paul’s language of grace as a transforming power received and cooperated with: “by the grace of God I am what I am, and his grace toward me was not in vain” (1 Corinthians 15:10); “work out your own salvation with fear and trembling, for it is God who works in you” (Philippians 2:12-13). The sacramental grounding: “you were washed, you were sanctified, you were justified” (1 Corinthians 6:11). The beatific vision as telos: “now we see in a mirror dimly, but then face to face” (1 Corinthians 13:12).

For progressive sanctification and glorification: “those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified” (Romans 8:30). The progressive dimension: “being transformed into the same image from one degree of glory to another” (2 Corinthians 3:18). The eschatological consummation: “when Christ who is your life appears, then you also will appear with him in glory” (Colossians 3:4).

Scripture speaks with all three voices. It uses the language of participation, of sanctifying grace, and of progressive transformation and future glorification — without choosing among them.

Patristic and Historical Roots

Theosis is not a late Byzantine development. It is present in the earliest Fathers. Irenaeus writes: “the Word of God, our Lord Jesus Christ, who did, through His transcendent love, become what we are, that He might bring us to be even what He is Himself” (Adversus Haereses 5, preface, c. 180). Clement of Alexandria speaks of the Christian becoming “god” by participation (Protrepticus 1 [*]). Maximus the Confessor (seventh century) provides the mature synthesis: theosis is the final cause of creation, and the Incarnation is the means by which nature is united to grace without confusion.

Sanctification through grace has deep roots in the Western Fathers. Augustine’s anti-Pelagian writings insist that grace is not merely pardon but transformation: God gives what He commands (Confessions 10.29.40). The Scholastic tradition formalizes this as “infused grace” — a created participation in the divine nature that inheres in the soul. The Council of Trent defines justification as “not only the remission of sins, but also the sanctification and renewal of the interior man” (Session 6, Chapter 7, 1547).

Progressive sanctification has patristic support in the Western tradition’s emphasis on the pilgrim character of the Christian life — Augustine’s peregrinus motif — and in the Reformers’ recovery of the eschatological tension between the “already” and the “not yet.” Calvin, despite his emphasis on forensic justification, insists that justification and sanctification are inseparable gifts of union with Christ (Institutes 3.11.1). Wesley’s doctrine of “entire sanctification” presses the transformative dimension further than most Reformed theology is comfortable with, but it shares the same basic grammar.

The Case for Compatibility

The compatibility is genuine and relatively strong.

All three traditions affirm the following: (1) the believer is really changed, not merely legally reclassified; (2) this change is the work of divine grace, not human effort; (3) the change has an eschatological horizon — it is completed only in the age to come; (4) the change involves genuine participation in the divine life, however that participation is described.

The differences are primarily differences of emphasis and vocabulary, not of substance:

• The East emphasizes the ontological dimension — the creature’s real participation in divine life — and has the richest vocabulary for it.
• Rome emphasizes the sacramental mediation of that transformation and its teleological culmination in the beatific vision.
• The Reformation emphasizes the eschatological tension and the Christological ground — the believer is transformed in Christ, by the Spirit, toward the resurrection.

These are not contradictory claims. They are three windows opening onto the same landscape. The Eastern window reveals the height of the mountain (what we are becoming); the Catholic window reveals the path up the mountain (the sacramental means); the Protestant window reveals the distance still to travel (the eschatological “not yet”).

The convergence is not merely theoretical. The Finnish school of Luther interpretation (Tuomo Mannermaa and his students) has argued persuasively that Luther’s own theology of union with Christ (in ipsa fide Christus adest — “in faith itself Christ is present”) contains a participatory ontology surprisingly close to the Eastern doctrine of theosis [*]. Whether this reading of Luther is correct is debated, but the fact that the argument can be made at all demonstrates the proximity of the traditions.

The Boundary with Layer 4

The diversity becomes a faultline if theosis is pressed to mean that the creature becomes God in essence — that the distinction between Creator and creature is dissolved. This would be pantheism, and every Orthodox theologian of note explicitly rejects it. Palamas’s essence-energies distinction exists precisely to prevent this conclusion: we participate in God’s energies (His self-communication, His glory, His grace) but never in His essence (His inner being). The distinction is itself disputed by Western theology (Aquinas rejects it), but the theological intent — to affirm real participation while preserving the Creator-creature distinction — is shared.

A second boundary: if Protestant “sanctification” is reduced to mere moral improvement — behavior modification without ontological transformation — it falls below the scriptural and patristic witness. The believer is not merely trying harder; the believer is being made new (2 Corinthians 5:17). Most serious Protestant theology affirms this, but popular Protestant piety sometimes loses it.

A third boundary: the question of whether the beatific vision involves seeing the divine essence (Aquinas, Benedict XII’s Benedictus Deus, 1336) or the divine energies (Palamas) is a genuine metaphysical disagreement. It is addressed in Layer 4 to the extent that the essence-energies distinction itself becomes a contested doctrinal claim rather than a philosophical framework.

For Further Study

• Athanasius, On the Incarnation (De Incarnatione), especially chapters 54-57
• Gregory Palamas, The Triads (c. 1338-1341)
• Thomas Aquinas, Summa Theologiae I-II, qq. 109-114 (on grace)
• Vladimir Lossky, The Mystical Theology of the Eastern Church (1944)
• Tuomo Mannermaa, Christ Present in Faith: Luther’s View of Justification (2005) [*]