Winger, Thomas M. "Introduction: Structure and Rhetoric." Ephesians. St. Louis: Concordia Publishing House, 2014, 148-163.
Winger provides a brief format of standard epistolary structure at the time of Paul (Winger 2014, 148-149). Paul's letter to the Ephesians, along with his other letters, follow the standard style rather closely. Paul's thanksgiving and prayers for the recipients, found in the introduction, tend to be more theologically oriented and elaborate than those of the average writer. Winger notes that Ephesians contains both a Berakah prayer (1:3-14) according to a traditional Jewish model, and also a normal thanksgiving (1:15-23) (Winger 2014, 149).
The conclusion of Paul's letters normally follows a pattern as well, with a request for prayer, a commendation of the one who is to deliver the letter, a greeting of peace, and a message of grace and fellowship. These elements, again, are relatively common elements, especially in Christian letters (Winger 2014, 150).
The body of the letter, found between the greeting and conclusion, is also according to a fairly standard period structure, but Paul has customized it to fulfill his epistolary purposes. He devotes the first portion of the body to what Winger describes as "doctrinal," "kerygmatic," or "indicative." He describes the doctrinal view he has in mind. In the second portion, he provides what Winger describes as "ethical," "didactic," or "imperative." He tells the recipients how to live (Winger 2014, 1521). There is normally a substantial doxology at the end of the first section. Winger does observe that the placement and use of doxologies, and even the broad categories of the material in the pattern is not necessarily reflective of the intricate ways Paul approaches his material (Winger 2014, 152).
From a rhetorical standpoint, Winger takes all of Paul's epistles to fit the category of a "sermon" or a "liturgical proclamation" (Winger 2014, 153). The message is intended as a persuasive argument to be delivered orally, though by reading aloud as opposed to being a speech delivered by the author. Winger provides a brief summary of the steps any author, including Paul, would go through in the process of developing a clear case (Winger 2014, 154ff). He suggests that, for the most part, Ephesians fits a pattern of epideictic rhetoric, "appealing to the crowd to hold or reaffirm a point of view" (Winger 2014, 156). Chapters 1-3 fit this pattern well, though chapters 4-6 may move to a more deliberative mode, urging future action. However, at some point, Winger observes, the categorization breaks down, especially as we consider that the Gospel is primarily a matter of proclamation as opposed to prescription of behaviors (Winger 2014, 157). The overall structure of Ephesians consists of an exordium and narratio, in which Paul lays out the essential arguments, using some typical Jewish patterns (Winger 2014, 150). All the arguments in Ephesians are related to the unity the body of Christ has in relation to the baptismal life. He then moves into an argumentio, which provides proofs of unity and refutations of the efficacy of the old, unregenerate lifestyle (Winger 2014, 160). He then moves to his peroratio, a conclusion of his argumentation (Winger 2014, 161). The conclusion he makes is that as the Christians put on the armor of God they are equipped to live the baptismal life of unity in Christ.