Book of Philemon
The Epistle to Philemon is a book of the Bible in the New Testament. Philemon is generally regarded as one of the undisputed works of Paul, and it was most likely written in Rome, around 61-63 AD. It is the shortest of Paul's extant letters, consisting of only 25 verses. This epistle, along with epistles to the Ephesians and Colossians, was carried by Tychicus, a disciple and companion of Paul's.
Purpose of the epistle
Paul addressed the epistle specifically to Philemon, his fellow apostle. Paul appeals directly to Philemon's Christian conscience in asking him to accept the return of Onesimus, a runaway slave of Philemon's. Paul indicates that he converted Onesimus to Christianity (1:10-11), therefore making him "profitable" (or "useful"). Paul implores Philemon to treat Onesimus not as a slave but, like Paul, as a brother in Christ.
Additionally, Paul offers to take on all debts and transgressions that Onesimus owed to Philemon, just as Christ took on the sins of Man.