In Philippians 2:5-11, Paul stops writing a letter and starts writing a Hymn. Face-to-face with Jesus, he can do nothing but worship his humility, obedience, and glorious Lordship. Paul has been patiently admonishing his brothers and sisters in Philippi to stop living as citizens of Rome and start living as citizens of heaven - this is his why, or rather his who: the glorious Christ who is humility incarnate.