When we come to the office of the bishop, we can once again trace it back to the New Testament, this time to the word episcopos, which quite literally means an “overseer”. It is apparent, however, that in the New Testament episcopos and presbuteros are interchangeable terms. The biblical authors do not differentiate between them. Indeed, in the passage we read from 1 Peter, the apostle exhorts the elders (presbuteroi) to serve as overseers (episcopoi).
If there is any distinction to be made, it may be that presbuteros was the term used by Jewish congregations deriving from the synagogue and episcopos was the word that the primarily Gentile churches employed. Michael Green also helpfully points out that, while the word “presbyter” indicates an office within the church, “overseer” describes its function.
Of bishops or episcopoi Paul writes,
Here is a trustworthy saying: If anyone sets his heart on being an overseer [episcopos], he desires a noble task. Now the overseer must be above reproach, the husband of but one wife, temperate, self-controlled, respectable, hospitable, able to teach, not given to drunkenness, not violent but gentle, not quarrelsome, not a lover of money. He must manage his own family well and see that his children obey him with proper respect…. He must not be a recent convert, or he may become conceited and fall under the same judgment as the devil. He must also have a good reputation with outsiders, so that he will not fall into disgrace and into the devil’s trap.
It is clear from what Paul writes that the bishop must be a person of spiritual maturity and personal integrity. As with the presbyter, the episcopos has a ministry both to the congregation and to those outside. Once again, this is reflected in the Prayer Book Ordinal, where the newly consecrated bishop is exhorted,
Be to the flock of Christ a shepherd, not a wolf; feed them, devour them not. Hold up the weak, heal the sick, bind up the broken, bring again the outcasts, seek the lost. Be so merciful, that you be not too remiss; so minister discipline, that you forget not mercy: that when the chief Shepherd shall appear you may receive the never-fading crown of glory…
It is ironic, and not a little revealing, that these words, addressed to bishops, are derived from words which in the New Testament are addressed to elders.
If we cannot find biblical justification for separate offices of bishops and priests, there is good evidence that within a century or so of the New Testament period the two offices began to be distinguished from one another. Gradually, presbyters became associated with a local congregation, while bishops took on a more regional role.
There are good historical reasons for this development. By and large, new churches were formed as daughters of earlier congregations, usually centered in the larger towns or cities. Initially these churches would have had as their pastors a group of elders with a shared ministry, of whom one might have been designated as the chief pastor or bishop. Eventually the mother church would have become known as a cathedral and the bishop’s role more specialized and less localized. Among other functions, the bishop would have represented the churches at larger gatherings and consultations and conversely would have brought the resolutions of those convocations back to his local area (or diocese).
The term diocese, by the way, was simply one which the church borrowed from the secular Roman world. It referred to an administrative district within a province.