What does Philemon 1:2 mean?

Two people and one important group are mentioned in this verse. Apphia was likely the wife of Philemon, and a convert to Christianity, as she is called "sister." Archippus was probably Philemon and Apphia's son, and also a strong Christian, whom Paul calls a "fellow soldier." This is not a reference to serving in the military, since Paul and Timothy were not members of an earthly army. Rather, this is a spiritual description. In Colossians 4:17 Archippus is told to fulfill the ministry he had been given by God. So, he clearly had some calling as a Christian leader among his peers.

The group mentioned is the church which met in Philemon's home. This is a reference to the Colossians' church, a group which also received a Prison Epistle from Paul. The fact that this church met in Philemon's home implies that his house was fairly large. This also says something about Philemon's hospitality. The church in Colossae consisted of Gentiles (Colossians 1:27) who likely used Greek as their main language. Some false teachings were promoted in their area (Colossians 2:16–23). The Colossian Christians had been trapped in sinful lives prior to coming to faith in Jesus (Colossians 3:5–11), but were now changed. Their fellowship time included singing (Colossians 3:16), and a diverse group of young and old, freedmen and slaves, men and women (Colossians 3:18–22).