When we look at the New Testament, almost every book has a clear purpose. The Gospels present the life of Jesus. Acts shows the power of the Holy Spirit working through the early believers. Romans presents the gospel in depth. Hebrews demonstrates that Jesus is better.
There are a few New Testament books whose purpose is less clear. Philemon is one of those books. In His sovereignty, God included this little book in the canon of Scripture. Therefore, this little book has something to add. It is essential in some way. There is a unique point that this book is supposed to make for us.
The main point of the book of Philemon can be found in the story of this letter.
The Story of Philemon
In Acts 19, the apostle Paul spent three years in Ephesus (55-57 AD). For two years, he trained leaders at Tyrannus, who in turn shared the gospel, made disciples, and planted churches across Asia Minor. The result was that “all the residents of Asia, both Jews and Greeks, heard the word of the Lord” (Acts 19:10).
One of the men who was trained during this time was Epaphras. Epaphras pioneered the gospel work in Colossae, Laodicea, and Hierapolis (Col 1:8; 4:12-16). Although Paul had never visited Colossae, his disciple, Epaphras planted a church in that city.
A few years after he left Ephesus, Paul was under house arrest in Rome for two years (60-62 AD). During that time, he was reunited with Epaphras, who was also in prison (Philem 23). From the time of his imprisonment, Epaphras labored in prayer for his churches that were left behind. In fact, one of the purposes of Paul’s letter to the Colossians was to establish Archippus in his ministry, likely to replace the role left by the arrest of Epaphras (Col 4:17). It seems that Epaphras encouraged Paul to write the letter to the Colossians to continue to help that church to grow despite the adversity occurring that led to Epaphras’ arrest.
Paul’s letter to Philemon was sent simultaneously as Paul’s letter to Colossians and is something of a subplot of what happened in that letter (click here for a Missionary’s Reflection on Paul’s Letter to the Colossians). We can tell that they were written at the same time because the two letters have the same circumstances. In both letters, Paul was in jail with Epaphras (Col 4:12-16; Philem 23). In both letters, Paul sent Onesimus back to Colossae (Col 4:9; Philem 12). In both letters, Mark, Aristarchus, Demas, and Luke were with Paul (Col 4:10, 14; Philem 24). Also, the same Archippus who was to take leadership in Colossae was one of the three recipients of Paul’s letter to Philemon. Lastly, in Colossians 4:9, Onesimus was described as “one of you,” meaning that he was from Colossae. As an aside, Paul described ten of his coworkers in this short letter, which is a picture of the need of modern missionaries to develop more coworkers for the gospel!
The main point of Paul’s letter to Philemon has to do with the slave, Onesimus, and his relation to Philemon and Paul. Philemon is described as a coworker of Paul, meaning that he was involved in missionary activity (Philem 1). Onesimus was a slave of Philemon who had come to be with Paul and Epaphras during their time in Rome. Many have assumed that Onesimus was a runaway slave, although the text does not say that he was a runaway. In fact, it is implausible that Onesimus, as a runaway slave, would have randomly come into Paul and Epaphras’ contact while they were in prison. They could not have been in the same jail since Paul was a Roman citizen under house arrest. A slave would have been kept in far worse conditions.
Instead, it is most likely that Philemon sent Onesimus to Paul and Epaphras to care for them during their imprisonment. Similarly, the Philippian church had sent Epaphroditus to Paul (Phil 2:19-30). Philemon and the church meeting in his home had likely sent a financial gift by the hand of Onesimus.
During his time with Paul, Onesimus had a life-changing encounter with Jesus. Paul now described Onesimus as “my son,” saying that “I became his father while I was in chains” (Philem 10). Paul described Onesimus as “my very own heart” (Philem 12). In a wordplay on Onesimus’ name, Paul said he was formerly useless (Gr. achreston) to Onesimus, but now had become useful (Gr. euchreston) to both Paul and Onesimus.
Now Paul asserted that Onesimus’ status had changed. He sent Onesimus back to Philemon, although he wanted Onesimus to remain with him (Philem 13). Paul shares an expectation that Philemon will consent to do a “good deed,” without explicitly stating what this good deed was (Philem 14). In the context, it seems that Paul’s expectation was that Philemon was releasing Onesimus from his slavery and send him to Paul to join Paul’s missionary team. As a Pauline coworker, Onesimus was to be treated “as a dearly loved brother” (Philem 16). In fact, Paul commanded Philemon to “welcome [Onesimus] as if you would me” (Philem 17).
Therefore, Onesimus returned to Colossae with Tychicus, the letter carrier of Paul’s letters to Ephesus and Colossae (Eph 6:21-22; Col 7-9). He may have been the same Onesimus described by Ignatius of Antioch as the leader of the church of Ephesus in c. 107 AD.
The Purpose of Paul’s Letter to Philemon
Having reviewed the story of Paul’s letter to Philemon, we can now return to this short letter’s purpose. Paul’s purpose in writing this letter was to gain permission for Onesimus to join his missionary team. Paul was careful to do this so as not to offend another missionary coworker, Philemon. Therefore, Paul’s entire purpose in writing his letter to Philemon was to establish another coworker for the gospel.
This means that God, in His sovereignty, included a whole New Testament book whose primary purpose was for a missionary leader to add another member to their missionary team. This little book, then, becomes one more indication in the New Testament of the value of missionary teams. It also provides a picture of how a missionary leader appealed to a local church’s leadership to send one of their members to join Paul in his missionary activity.
From Slave to Missionary
Paul’s Letter to Philemon is also a picture of the life-changing power of the gospel. Onesimus was a slave, described as “useless” to his master (Philem 11). As a slave, he owed a debt to his master (Philem 18). Since Philemon was not only a follower of Jesus but also a Pauline coworker, we should assume that he treated Onesimus well. However, when Onesimus encountered Jesus through Paul, his life was transformed. He became Paul’s spiritual son and useful for the gospel ministry. Onesimus was manumitted from slavery and launched directly into ministry as Paul’s apprentice and helper.
This story provides insight into how the apostle Paul viewed those around him. While others saw a slave at the bottom of society, Paul saw a potential leader. Imagine how easy it would have been for Paul to overlook Onesimus. As a leader, it would have been easy for Paul to see Onesimus’ only value as serving him. After all, Onesimus was “only a slave.” However, Paul, like Jesus, saw the people who were around him. He saw potential in Onesimus and was ready to tap his potential.
At the same time, Paul knew that if he took Onesimus as his coworker without Philemon’s willing agreement that he could break relationships in Colossae. In this letter, Paul masterfully appealed to Philemon for Onesimus in such a way that Philemon could not say no while being sure to give Philemon credit for his generosity. For example, Paul wrote,
“But I didn’t want to do anything without your consent, so that your good deed might not be out of obligation, but of your own free will.” Philemon 14
“And if he has wronged you in any way, or owes you anything, charge that to my account. I, Paul, write this with my own hand: I will repay it – not to mention to you that you owe me even your very self.” Philemon 18-19
Here is the point. If a slave can become a missionary coworker of Paul, then so can anyone. As Paul wrote somewhere else,
“Brothers and sisters, consider your calling: Not many were wise from a human perspective, not many powerful, not many of noble birth. Instead, God has chosen what is foolish in the world to shame the wise, and God has chosen what is weak in the world to shame the strong. God has chosen what is insignificant and despised in the world – what is viewed as nothing – to bring to nothing what is viewed as something.” 1 Corinthians 1:26-28
The book of Philemon is ultimately about the life-changing power of the gospel. The gospel is so powerful that it can transform the lowest in society into men and women worthy of taking the gospel to the ends of the earth.
 Ignatius to the Ephesians 1.3, 2.1.