Why do you do good works? Philemon

Philemon 1:6-7 (NASBStr)

and I pray that the fellowship of your faith may become effective through the knowledge of every good thing which is in you for Christ’s sake. For I have come to have much joy and comfort in your love, because the hearts of the saints have been refreshed through you, brother.

In order to understand the above prayer of Paul for Philemon we have to recall the purpose Paul is writing this little letter.   Paul, while in prison had run into a young man named later in the letter as, Onesimus.    Onesimus, apparently, had been arrested in tossed in the same prison system as Paul.  Paul, as Paul did in prison, leads him to The Lord.     In their dialogue they discover they have a mutual acquaintance:  Philemon.   However, Philemon had a different relationship with each.  To Paul, Philemon was a friend.   To, Onesimus, Philemon was his previous owner and someone he must have stolen from and ran away from his slavery.   Paul wanted Philemon to show his continuous Christian love and faith by taking Onesimus back and forgiving him and letting Paul pay for his offense; just as Christ paid for Philemon's sin.   Paul begins his request of Philemon by remembering the good love and faith he has expressed solidly within the Christian community.   Paul's prayer, above, is that that type of Christian love would be heard, observed and known by all those who knew of such love to enable them to praise God and come to the same joy in Christ that Paul was experiencing.   Paul knew the power of a great example of love.  He prayed that Philemon's entire life would be on display to the Christian community.   Paul wanted Philemon's example of Christian love to "become effective through the knowledge of every good thing which is in you for Christ's sake."   Any good that we do is for the purpose of being on display for God's glory.   Christ told us in the Sermon on the Mount to let our good works show before men so that they will see them and praise and glorify God.  This prayer and story is an example of what Jesus was talking about.   When we do a good work we ought not do it to get praise from men but we ought to do it so that men, when they see it, praise God.