In the OT there was a ministry of priests and Levites in the Temple, and in NT times synagogues had an official ministry (Luke 4: 20; Acts 18: 8). Paul gives a list of ministries operating in the Church and all are equally inspired by the Spirit: there are apostles, prophets, teachers, evangelists, and pastors (1 Cor. 12: 28; Eph. 4: 11), though he does not here define duties and qualifications. Later, the duties of bishops, elders, and deacons are more carefully explained in Acts 20: 17, 28; 1 Tim. 3: 1, 8; Titus 1: 5, 7. The threefold ministry of the Church taking the form of bishops, presbyters, and deacons later sprang from these roots. The first leaders of the Church, apostles, did not perpetuate their office, but an ‘apostolic ministry’ of witness to the Risen Christ was continued by local leaders. At first they (e.g. Timothy) acted under the general oversight of the apostles (Phil. 2: 19–24) and there were groups of presbyters at Jerusalem under the presidency of James. The structure was probably borrowed from the synagogue.
Timothy and Titus are regarded in the Pastoral Epistles as Paul's delegates in ministry and appointed by him by a laying on of hands (2 Tim. 1: 6). Timothy and Titus in their turn appointed elders (presbyters) in every town (Titus 1: 5) or bishops (episcopoi, Titus 1: 7; 1 Tim. 3: 1–7), who again must appoint successors (2 Tim. 2: 2). There must be an unbroken succession of apostolic teaching. The duties of deacons are specified in 1 Tim. 3: 8–13.
It is unclear whether the ‘bishop’ of 1 Tim. 3: 1 is one of the elders of 1 Tim. 4: 14 who ‘rule’ (1 Tim. 5: 17) or whether the bishop is a single presiding minister. Possibly elders exercised corporate leadership in house communities while the apostle or his delegate was absent, but eventually the local authority yielded to the leadership of one in the city who had special gifts of teaching. He became the president (episcopos) and on him devolved duties (but not of course that of being a witness of the Risen Christ) of the original Twelve and Paul. In Asia Minor a ministry of presbyters existed (1 Pet. 5: 1, 5) and they formed a corporate defence against the destruction of the Church by persecution. They were under‐shepherds under the chief shepherd, Christ; Peter the apostle, a ‘fellow elder’ had authority to address the Asian elders. Cf. 2 and 3 John.
Thus in the 1st cent. there existed both a local ministry and a general, apostolic ministry and their work as presidents was to enable sinners to offer a pure and acceptable sacrifice to God by pleading Christ's sacrifice (Rom. 15: 16). As servants of Christ (Eph. 4: 12) and under‐shepherds of the Chief Shepherd (1 Pet. 5: 2–4) they have an authority over his people.