A Faith that Testifies

In this letter to Philemon, Paul reminds him that he thanks God for Philemon's faith and trust towards Jesus Christ. He thanks God for hearing about Philemon's love of Jesus Christ and the love shown to all the saints.
As such, he expects Philemon to forgive Onesimus, a one time servant of his, as if he had never stole anything from him. If Philemon truly has the spirit of Christ in him it will show in his forgiveness, reception and acceptance of Onesimus as a brethren and one of the saints.
What kind of testimony would Philemon demonstrate by showing love and grace toward Onesimus? Can we have this this same "Faith that Testifies"