Elders That Rule Well

How are the terms Pastor, Deacon, Bishop and Elder used in Scripture and what are the different functions of each? What are the characteristics of those that rule well according to the Scripture? Do Elders have a physical age requirement or is it a Spiritual maturity that's required? In order to 'rule well' according to Scripture, is it the most important thing for an Elder to persuade the sheep to rest in the peace of Christ during times of trouble? The Faith that Paul says to follow is it the faith of the preacher or the object of Faith which is Christ? Should those that labor in the True Word be valued and honored in their person? Are Elders subject to criticism for setting forth the True Gospel of Christ? Why does the LORD allow infirmities on His preachers?