Salvation creates servants. The introduction to Philippians focuses on Paul as servants, then the overseers and deacons who serve the church's spiritual and practical needs. This letter is how Paul serves the church at Philippi, doing what Jesus asks of him.
Overseers and deacons are to be qualified. These qualifications are described in Titus and Timothy. The condition of our walk with God affects others in the church.
Salvation leads to servanthood, the fruit of being like Christ