Beloved Brother or Slave?

Addressing Philemon as well as the church that meets in Philemon's house, Paul makes this prayer: "I pray that the koinonia of your faith may become effective when you realize all the good that we may do for Christ" (vv. 4-6). What was Paul's intention in revealing the content of his prayer for Philemon in a letter he knew would be read publicly? Why was Philemon's koinonia of faith both a matter of praise and an object of concern for Paul? The text does not answer these questions until ten vers