Paul's letters sit in the Bible in order of length, not date
Thirteen New Testament books carry Paul's name, but most scholars think he wrote only seven of them. Their running order in Bibles follows a simple rule: longest first, with the pastoral letters to individuals set apart at the end. Several letters Paul mentions have vanished, and forged ones circulated for centuries.
Scholarly consensus accepts seven letters as authentically Paul's, among them Romans, Galatians and 1 Thessalonians, which rank among the earliest surviving Christian documents. Three, the letters to Timothy and to Titus, are widely considered written later by others in his name. On three more, including Ephesians and Colossians, opinion is split roughly evenly; defenders note that Colossians has distinctive Pauline stylistic traits. Critics of the doubters counter that arguments from style and vocabulary are subjective, and that early Christians consistently rejected forgeries.
Paul's working methods complicate the question. He says in several letters that he used secretaries, sometimes naming them, and some scholars think physical problems such as poor eyesight or damaged hands made dictation necessary. Candida Moss has argued that enslaved and formerly enslaved scribes played an overlooked part in producing these texts. Letter collecting was an established genre, practised by Cicero, Seneca and Pliny the Younger, and such collections were often arranged by subject or recipient and expanded after an author's death. David Trobisch thinks Paul probably assembled his own letters for publication.
The manuscript order is strikingly consistent: descending length of the Greek text, with Galatians the one oddity, placed ahead of the slightly longer Ephesians. Hebrews, which never names its author, was long counted among Paul's letters, though Rome doubted it; opinion turned firmly against Paul from the sixteenth century. Jerome's fourth-century Vulgate popularised placing it after the Pauline letters.
Paul's own words refer to lost correspondence, including an earlier letter to Corinth and a so-called Severe Letter written between the two that survive. Forgeries filled such gaps: a second-century Third Epistle to the Corinthians, once accepted by Armenian and Syriac churches; a Latin letter to the Laodiceans patched together from Philippians; and an exchange between Paul and the philosopher Seneca, universally judged a fourth-century fake.
Source: Pauline epistles
