In light of Paul’s calling as an apostle of Christ Jesus, not only to preach the Gospel but also to strengthen, encourage and exhort the fledgling converts, we may understand the aim of his epistolary writings broadly speaking as letters written for the purpose of persuading. Thus, we may understand Paul’s letters as rhetorical in nature, crafted and designed to make an impact on its hearers and to inspire and move them to action of some sort. Regarding the structure of the letters, Brown observes that just as Greco-Roman letters typically exhibit a clear format, so too New Testament letters reveal a clear structure. In the format of the New Testament letters, four parts are distinguished: (1) an opening formula (praescriptio), (2) a thanksgiving section, (3) the body of the message, and (4) a concluding formula.
Typically, there are three elements in the opening formula: (a) the sender (superscriptio)-e.g., “Paul and Timothy servants of Christ” (Phil 1:1), “Paul, called to be an apostle of Jesus Christ” (1 Cor 1:1) , (b) the addressee(s) (adscriptio)-“to the church of God that is in Corinth” (1 Cor 1:2), and (c) the greeting (salutatio)-“grace to you and peace from God our Father and the Lord Jesus Christ” (Phil 1:2). In the Greco-Roman personal letter, one finds in the opening section a wish for good health; however, excepting 3 John, New Testament letters typically dispense with this element. Yet, as Brown notes, New Testament letters expand aspects of the opening formula with descriptions of the believers’ blessings and status in Christ. For example, in 1 Cor 1:4-9, Paul enumerates the ways in which the believers at Corinth have been enriched in Christ with spiritual gifts, which are of course to be used for God’s glory.
In the thanksgiving section, we find phrases such as, “I thank my God every time I remember you” (Phil 1:3), which, in contrast to the Hellenistic norm of giving thanks to a god for deliverance from situation x or person y, the thanksgiving is expressed for the faithfulness of the saints. Keck also notes that “the thanksgiving paragraph often modulates into an eschatological chord,” reminding the believers of their already-not-yet situation in salvation history. In addition, important themes are presented in the thanksgiving section-themes that will be further developed in the body of the letter (cf. Rom. 1:11-17).
As just mentioned, in the body of the letter, the major themes are elaborated, and here again we find certain fixed patterns and structures. Brown divides the body of the letter into three parts: (1) the Body-Opening, (2) the Body-Middle, and (3) the Body-Closing. In the Body-Opening section we typically find (a) an expression of joy of the news of the addressees’ well-being etc. (Phil 1:4; 2 Tim 1:4), and (b) a petition or request, which is a transition to the main message. Regarding (b), Brown enumerates five set properties: (i) “a background for petition is usually given first as a prelude, often in terms of joy over the state of the addressee”; (ii) “The petition itself is expressed in terms of one of four verbs of asking”; (iii) “The addressee is written to directly in the vocative”; (iv) “There is an expression of courtesy”; (v) “The desired action is described.” (pp. 416-17).
Because Brown devotes little attention to the Body-Middle section, I shall go directly to discuss the Body-Closing section. Here we have (a) a statement regarding the motivation of the letter (that is, an explanation of why the letter was written; e.g., Rom 15:14-16), (b) expectations of confidence regarding the desired response of the addressees (e.g., Phlm 21), and (c) travel plans, possible visits, and further forms communication are announced as well (e.g., Rom 15:22-29). Lastly, in the concluding formula, Paul again deviates from Greco-Roman conventions, as he never includes a wish for good health or a farewell. Paul does, however, retain an expression of greetings in this section (e.g., “The churches of Asia send greetings,” 1 Cor 16:19). In addition, Paul’s concluding formula also at times has a doxology, a benediction (e.g., “The grace of the Lord Jesus be with you,” 1 Cor 16:23), and the idea of greeting with “a holy kiss” (e.g., “Greet all the brothers and sisters with a holy kiss,” 1 Thess 5:26). As Keck brings to our attention, Paul will at times “add a final note” in his own handwriting (1 Cor 16:21-24), which is likely an indication that his letter was dictated. In sum, Paul’s letters are both like and unlike Greco-Romans letters. Both share certain basic structural similarities, but there are clear examples in which Paul departs from convention, and, as Wall puts it, “baptizes” the literary conventions in order to communicate and express distinctively Christian ideas and ways of being.
Works Cited/ Consulted
Brown, Raymond E. An Introduction to the New Testament. New York: Doubleday,
Keck, Leander E. “The Theology of Paul and the Theology of the Letters,” in Paul and
His Letters. (Minneapolis: Fortress Press, 1988): 16-32.
Wall, Robert W. “Introduction to Epistolary Literature,” in The New Interpreter’s Bible,
Vol X. (Nashville: Abingdon Press, 2002): 369-391.
 As Brown states, “[t]he NT letters, particularly the Pauline letters, were meant to be read aloud in order to persuade” (An Introduction to the New Testament, p. 411). Wall reminds us as well that Paul writes as a pastor “seeking to nurture his flock,” not as a scholar (“An Introduction to Epistolary Literature,” p. 381).
 Congruent with and Brown’s observations, Keck adds that Paul’s letters “embody Paul’s intense personal involvement in the issues but they were also designed to be read (aloud) in the congregations (1 Thess. 5:27; Philemon 2). Paul apparently wrote these letters as ‘stand-ins’ for his own presence. When a letter from Paul was read, it was as though Paul himself were speaking” (“The Theology of Paul and the Theology of the Letters,” p. 21). Keck has a helpful discussion of ancient rhetoric and how Paul’s letters correspond with the major parts of ancient discourses (exordium, narratio, peroratio) (cf. pp. 23-24).
 Cf. also, Wall’s discussion of the formal structures of epistolary literature, “An Introduction to Epistolary Literature,” pp. 380-83.
 Brown, An Introduction to the New Testament, p. 413.
 Brown, An Introduction to the New Testament, pp. 414-15.
 Keck, “The Theology of Paul and the Theology of the Letters,” p. 22.
 Keck, “The Theology of Paul and the Theology of the Letters,” p. 22.
 Brown, An Introduction to the New Testament, pp. 416-17.
 Brown, An Introduction to the New Testament, p. 417.
 Brown, An Introduction to the New Testament, p. 418.
 Keck, “The Theology of Paul and the Theology of His Letters,” 22-23.
 Wall, “An Introduction to Epistolary Literature,” p. 382. For example, Paul’s typical greeting, “grace” (charis) and “peace” (eirēnē) involves not only a departure from the Hellenistic salutation, chaire (“greetings”), but it also introduces a common Jewish greeting, shalom (“peace”). As Wall explains, “[t]he rhetorical effect of the salutation is two-fold: It addresses the audience as beneficiaries of God’s universal salvation and prefaces the subject matter of the letter by the essential promise of Paul’s gospel-that salvation is entered into by ‘grace’ and ‘peace’ with God is the result” (p. 380, italics added).