Of the four Prison Epistles, this is the only one written directly to an individual. Pauline authorship is self-evident through the repetition of his name (1, 9, 19). The listed associates were with Paul during his Roman confinement (1, 23–24). He identified himself twice as "a prisoner of Jesus Christ" (1, 9) and as "the aged" (9); both of these appellatives would fit into Paul’s life history at this time. Its similarity to Colossians (1–2, 23–24; cf. Col. 4:10–17) argues for a simultaneous writing from the same place by the same author. The book was listed within the Pauline section of the Muratorian Fragment and was acknowledged both as canonical and as written by Paul by these early Church Fathers: Ignatius, Tertullian, Origen, Eusebius, and Marcion.

Onesimus, a slave of Philemon who lived in Colosse, had stolen some of his master’s goods and fled to Rome (18–19). In the imperial city Onesimus somehow came into contact with Paul who led the slave into a saving knowledge of Christ during the apostle’s captivity (10). For a while Onesimus stayed in Rome and ministered to Paul’s material needs, perhaps as a house servant or chef (11, 13). Paul, however, knew that the slave had to be returned to his legal master (13–14). Since Tychicus was returning to the province of Asia with the letters to the Ephesians and Colossians (Eph. 6:21–22; Col. 4:7–8), Paul decided to send Onesimus back to Philemon with his letter messenger. The letter was thus composed to explain the situation to Philemon and to instruct the master as to how the runaway slave, now a Christian, should be received. This personal letter, then, was written from Rome during Paul’s first imprisonment (a.d. 60).

Some current liberal thinkers believe that the book was actually sent to Archippus, the real owner of Onesimus. To them, Philemon was the general overseer of the Christian work in Laodicea, Hierapolis, and Colosse with his residence in Colosse. Paul sent the letter and the slave first to Philemon who in turn brought them to Archippus. It was planned that Philemon would exert pressure on his understudy and that Archippus would comply with Paul’s request. In so doing, they equate the Book of Philemon with the "epistle from Laodicea" (Col. 4:16). Also, the fulfillment of Archippus’ ministry would be in the release of Onesimus (Col. 4:17). Although this novel approach appears plausible in places, it has not received acceptance by evangelical scholarship. Since Philemon was mentioned first, the book must have been written to him. If it had been written to Archippus, the text would have read "to the church in his house rather than "your house." Also, the simple explanation of Archippus’ ministry is the general ministry (perhaps the pastorate), not a specific task to set a designated slave free.

In this intimate letter Paul thus wrote to commend Philemon for his Christian compassion toward the needs of fellow believers (1–7); to effect the forgiveness and restoration of Onesimus by Philemon (8–21); to announce plans of a future visit, based upon his hopes of an imminent release (22); and to send greetings from many of Paul’s associates who were probably known to Philemon (23–25).

The finest human illustration of the theological concepts of forgiveness and imputation permeates this book. Paul earlier wrote: "And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ’s sake hath forgiven you" (Eph. 4:32). Human forgiveness should reflect divine forgiveness. To the spiritually sensitive, the personages of Paul, Philemon, and Onesimus symbolize respectively Christ, the Father, and the converted sinner. When Paul besought Philemon to receive the slave forever as Paul himself (12, 15, 17), the truth that God accepts believing sinners in the beloved one, Christ, takes on flesh. Paul also wrote: "If he hath wronged thee, or oweth thee ought, put that on mine account … I will repay it" (17, 18). This is the language of imputation (cf. 2 Cor. 5:19–21). The debt of the sinner (sin, guilt, and penalty) was paid by Christ’s redemptive death. The person who paid the debt is also the one in whom the believer finds an acceptable standing.

Although the Bible nowhere attacks directly the institution of human slavery, principles for the humane treatment of slaves are found everywhere (Eph. 6:5–9; Col. 3:22–4:1; 1 Tim. 6:1–2; 1 Peter 2:18–25). They were to be treated as people, not property. In this personal letter, however, there is a hint of a principle which if properly applied would lead a Christian master to release his slaves, especially those who were Christian. Paul wanted Philemon to receive Onesimus "not now as a servant [slave], but above a servant, a brother beloved" (16). He later added: "Having confidence in thy obedience I wrote unto thee, knowing that thou wilt also do more than I say" (21). The words more than I say provide the clue. Do they not contain Paul’s hope and prayer that Philemon would not only forgive Onesimus, but that he would also release him from the yoke of human bondage? The principle is clear: If God our heavenly master freed us who were slaves to sin, should we not also release men from human slavery if it is within our power to do so?

Paul and his associate Timothy sent this letter not only to Philemon, but also to Apphia, probably his wife, to Archippus, presumably his son, and to the assembly of believers that met in his house, possibly at Colosse. Thus, everyone would be aware of Onesimus’ conversion and of Paul’s request to Philemon concerning the runaway slave. In a sense Philemon’s decision would not be entirely private.

Paul then gave public thanks for Philemon’s love, faith, compassion, and kindness that were manifested both toward Christ and the believers. The apostle’s anticipated request was disguised within his prayer that "the communication of thy faith may become effectual by the acknowledging of every good thing which is in you in Christ Jesus" (6).

Paul could have exercised his apostolic authority by issuing a command to Philemon, but he chose to beseech him on the basis of love, age, and his imprisonment which no doubt caused Philemon some concern (8–9). He probably startled his friend when he named Onesimus as the object of his appeal. He proceeded to identify the converted slave in many ways: my son, whom I have begotten in my bonds, once unprofitable but now profitable, mine own bowels (cf. 7), and a brother beloved. The apostle informed Philemon that Onesimus had been profitable through his household ministry and that he had wanted to keep the slave in Rome, but he sent him back because he did not want to impose his desire upon Philemon (11–14). He then conjectured that God had used the slave’s theft and flight as the impersonal means to secure his eternal salvation (15). Paul next expressed his wish that Philemon would receive the slave as a brother beloved and even as the apostle (16–17). Paul offered to pay any debts owed to Philemon by the runaway. He used the fact that Philemon’s salvation was gained through Paul’s ministry as his "collateral" or foundation for the future payment (18–19). Both Philemon and Onesimus had one thing in common: both had been saved through Paul. Paul wanted Philemon to refresh his bowels, namely Onesimus (20; cf. 7, 12) just as he had expressed compassion toward others. The apostle then expressed his confidence that Philemon would obey his requests and even go beyond them.

Paul concluded by asking Philemon to prepare a lodging for him because the apostle believed that he would be released from his Roman captivity as a direct result of his friend’s prayers (22). Greetings were then extended to Philemon from Epaphras, the Colossian messenger who had also been imprisoned, Mark, Aristarchus, Demas, and Luke. A simple benediction ended the short letter.