Who was Apphia and why is she called "our sister"?
Philemon 1:2 (ESV)
2and Apphia our sister and Archippus our fellow soldier, and the church in your house:
As a result of the close connection between Philemon, Apphia, and Archippus, it is commonly understood that Apphia was Philemon’s wife and Archippus their son.1 When Paul calls Apphia our sister, he is acknowledging that she is a fellow believer and thus part of God’s people.2
2 and Apphia our sister and Archippus our fellow soldier, and the church in your house: