Actually the whole letter by Paul addressed to Philemon is a clear attempt by Paul to get a slave set free and returned to him.....
Paul puts the screws to Philemon in the letter, and the context is clearly that Paul wants the slave set free.....
The other thing I think I should point out is that we dare not ***ume that just because something is not addressed in the bible with the very same wording we are seeking that this somehow means the Bible has nothing to teach on a topic.
An example would be getting drunk and driving a car the wrong way on the road.
Does any Bible author clearly come out and condemn driving drunk on the wrong side of the road?.....no.
But we cant then ***ume that the Bible must agree with the practice of driving a car drunk just because we cant find it as clearly talked about as some person requests.
The context of the New Test is clearly that owning a slave is harmful and that if a slave gets a chance to be free he should take it, and that to be a good Christian a slave owner should allow his slaves to go free.
This is the teachings of the Bible, and it is true....