Philemon 1:1-2

"Paul, a prisoner of Christ Jesus, and Timothy our brother, To Philemon, our dear friend and fellow-worker, to Apphia our sister, to Archippus our fellow-solder and to the church that meets in your home."

Paul uses 5 terms to describe the spiritual bond he has with other Christians:

1. Brother

• This suggests a strong bond, a loving relationship of mutual care and concern,because they are of the same family - they have the same Father, whose perfect attributes the family try to exhibit.
  

2. Dear Friend

• You can choose your friends, but you can't choose your family. Not only is Paul joined to them by obligation, he counts them as his friends. They have all that really matters in common.

3. Fellow-worker

• He identifies a common goal in life, presumably here the spread of the gospel for the salvation of the nations.

4. Sister

• Paul thinks of Christian women with purity, respect and love, as he would a physical sister.

5. Fellow-soldier

• Paul acknowledges that they are united in a common cause, against a common enemy - not each other's secondary opinions, but against sin and Satan. They are different in many ways, but united in the promotion of loving worship of God across the globe.

So Paul is keen to emphasise the strength of the bonds he has with fellow believers, however different in character, temperament etc they may be; bonds established at the cross. My natural (sinful) tendency with other believers is to identify and accentuate differences, exploit weaknesses, build dividing walls. But Christ died to tear those walls down. Can I really afford to build them up again?