Philemon 1:6

‘That the fellowship (sharing in common) of your (S) faith may become effectual, in the knowledge of every good thing which is in you, unto Christ.’

His prayer was that Philemon, in sharing his faith with his fellow-believers by his many good offices and gifts (and thus hopefully towards Onesimus), might find that it becomes effectual in bringing him closer to Christ (‘effectual -- unto Christ’), while establishing him in the knowledge of every good thing that is within him. As he contemplates what Christ is doing in his life, making him more and more fruitful, and conscious of what the Spirit has worked within him, it brings him close to His Saviour.