From a historical-critical perspective, the authorship of Ephesians is heavily debated. While the letter explicitly claims to be written by “Paul, an apostle of Christ Jesus,” a significant majority of modern critical scholars classify Ephesians as Deutero-Pauline (or pseudepigraphal).

Scholars suggest it was likely written by a later disciple or admirer of Paul after his death, perhaps between 80–100 CE. The reasons for this assessment involve its distinct literary and theological style:

1. Vocabulary and Syntax: Ephesians contains over 80 words found nowhere else in Paul’s undisputed letters. It is written in a highly liturgical, sweeping, and almost hypnotic Greek style. The opening sentence of the Greek text is a single, massive, grammatically complex run-on sentence spanning 12 verses (1:3–14).

2. A Shift in Theology: In undisputed letters like 1 Corinthians, the word “church” (ekklesia) refers to a local gathering of believers. In Ephesians, the “Church” is an exalted, cosmic, universal entity. Furthermore, while Paul’s undisputed letters eagerly anticipate the imminent return of Christ, Ephesians seems to reflect a more settled, institutional phase of Christian history, where the church is preparing for a long-term presence in the world.

Whether written by Paul in a Roman prison or by a later disciple preserving his legacy, the letter does not address a specific crisis or heresy (like Galatians or Corinthians). Instead, it functions as a grand, meditative theological treatise. It explores the profound “mystery” of the gospel: that God is orchestrating a master plan to unite all of fractured creation—and specifically, divided humanity—under the cosmic lordship of Christ.

The structure of Ephesians is beautifully symmetrical. It is divided perfectly in half. The first three chapters are purely theological and declarative (what God has done), while the final three chapters are practical and imperative (how humans should live in response).

Part I: The Cosmic Master Plan and the Unity of Humanity (Chapters 1–3)

The letter opens with a soaring, liturgical poem praising God the Father for choosing, predestining, and adopting believers before the foundation of the world. The author declares the ultimate goal of history: to gather up all things in heaven and on earth, and unite them in Christ.

In Chapter 2, the author shifts from the cosmic to the human level, focusing on the greatest social divide in the ancient world: the ethnic and religious chasm between Jews and Gentiles. He notes that the Gentiles were formerly “alienated from the commonwealth of Israel” and “without God in the world.”

However, through the cross, Christ has achieved an unprecedented sociological miracle. He has destroyed the “dividing wall of hostility” (a metaphorical reference to the physical wall in the Jerusalem Temple that separated the Court of the Gentiles from the Jewish sanctuary). By abolishing the divisive requirements of the Law, Christ took two hostile groups and created in himself “one new humanity” in place of the two, making peace.

In Chapter 3, the author calls this specific ethnic unification the “mystery of Christ”—a secret hidden for generations but now revealed to the apostles. He prays that the community may have the strength to comprehend the unimaginably broad dimensions of Christ’s love.

Part II: Walking Worthy of the Calling (Chapters 4–6:9)

At the hinge of the letter (Chapter 4), the author pivots with the word “Therefore,” urging the readers to “lead a life worthy of the calling to which you have been called.”

The ethical instructions that follow are deeply grounded in the theology of unity established in the first half. Because the Church is a single, organic body animated by one Spirit, the believers must strip off the “old self” (characterized by deceit, anger, and stealing) and put on the “new self.” They are commanded to speak the truth, share with the needy, and forgive one another just as God in Christ has forgiven them.

In Chapters 5 and 6, the author addresses the Greco-Roman Household Codes (Haustafeln). In the 1st-century Roman Empire, the hierarchical submission of wives to husbands, children to fathers, and slaves to masters was considered the bedrock of a stable society. The author adopts this cultural structure but subtly subverts it with a radical opening premise: “Be subject to one another out of reverence for Christ.”

While he tells wives to submit to their husbands, he lays a crushing, unprecedented demand on the husbands: they must love their wives “just as Christ loved the church and gave himself up for her.” Likewise, while slaves are told to obey their masters, the masters are commanded to stop threatening their slaves, reminding the masters that they too have a Master in heaven with whom “there is no partiality.”

Part III: The Armor of God (Chapter 6:10–24)

The letter concludes with one of the most famous metaphorical passages in Christian literature. The author warns the community that their ultimate struggle is not against flesh and blood (human enemies), but against cosmic, spiritual forces of evil in the heavenly places.

To survive this spiritual conflict, believers are commanded to put on the “whole armor of God.” Drawing on the imagery of a heavily armed Roman legionary, the author repurposes the military gear as virtues: the belt of truth, the breastplate of righteousness, shoes ready to proclaim the gospel of peace, the shield of faith (to extinguish the flaming arrows of the evil one), the helmet of salvation, and the sword of the Spirit, which is the word of God. The letter ends with a final appeal for prayer and a blessing of peace and grace.