Clement of Rome

Clement of Rome, Chapter 42, is one of the earliest references to bishops outside of the New Testament.

The apostles have preached the Gospel to us from Or, “by the command of.” the Lord Jesus Christ; Jesus Christ [has done so] from Or, “by the command of.” God. Christ therefore was sent forth by God, and the apostles by Christ. Both these appointments, Literally, “both things were done.” then, were made in an orderly way, according to the will of God. Having therefore received their orders, and being fully assured by the resurrection of our Lord Jesus Christ, and established Or, “confirmed by.” in the word of God, with full assurance of the Holy Ghost, they went forth proclaiming that the kingdom of God was at hand. And thus preaching through countries and cities, they appointed the first-fruits [of their labours], having first proved them by the Spirit, Or, “having tested them in spirit.” to be bishops and deacons of those who should afterwards believe.

This is early evidence that the ministry of bishops continued beyond the establishment in Acts. However, the role of bishops here seems once again to be that of local church pastor.