At the same time he laid down no minute arrangements, but only the simple and necessary elements of an organization, wisely leaving the details to be shaped by the growing and changing wants of the church in different ages and countries. In this respect Christianity, as a dispensation of the Spirit, differs widely from the Mosaic theocracy, as a dispensation of the letter.
The ministerial office was instituted by the Lord before his ascension, and solemnly inaugurated on the first Christian Pentecost by the outpouring of the Holy Ghost, to be the regular organ of the kingly power of Christ on earth in founding, maintaining, and extending the church. It appears in the New Testament under different names, descriptive of its various functions: -- the "ministry of the word," "of the Spirit," "of righteousness," "of reconciliation." It includes the preaching of the gospel, the administration of the sacraments, and church discipline or the power of the keys, the power to open and shut the gates of the kingdom of heaven, in other words, to declare to the penitent the forgiveness of sins, and to the unworthy excommunication in the name and by the authority of Christ. The ministers of the gospel are, in an eminent sense, servants of God, and, as such, servants of the churches in the noble spirit of self-denying love according to the example of Christ, for the eternal salvation of the souls intrusted to their charge. They are called -- not exclusively, but emphatically -- the light of the world, the salt of the earth, fellow-workers with God, stewards of the mysteries of God, ambassadors for Christ. And this unspeakable dignity brings with it corresponding responsibility. Even a Paul, contemplating the glory of an office, which is a savor of life unto life to believers and of death unto death to the impenitent, exclaims: "Who is sufficient for these things?"  and ascribes all his sufficiency and success to the unmerited grace of God.
The internal call to the sacred office and the moral qualification for it must come from the Holy Spirit,  and be recognized and ratified by the church through her proper organs. The apostles were called, indeed, immediately by Christ to the work of founding the church; but so soon as a community of believers arose, the congregation took an active part also in all religious affairs. The persons thus inwardly and outwardly designated by the voice of Christ and his church, were solemnly set apart and inducted into their ministerial functions by the symbolical act of ordination; that is, by prayer and the laying on of the hands of the apostles or their representatives, conferring or authoritatively confirming and sealing the appropriate spiritual gifts. 
Yet, high as the sacred office is in its divine origin and import, it was separated by no impassable chasm from the body of believers. The Jewish and later Catholic antithesis of clergy and laity has no place in the apostolic age. The ministers, on the one part, are as sinful and as dependent on redeeming grace as the members of the congregation; and those members, on the other, share equally with the ministers in the blessings of the gospel, enjoy equal freedom of access to the throne of grace, and are called to the same direct communion with Christ, the head of the whole body. The very mission of the church is, to reconcile all men with God, and make them true followers of Christ. And though this glorious end can be attained only through a long process of history, yet regeneration itself contains the germ and the pledge of the final perfection. The New Testament, looking at the principle of the now life and the high calling of the Christian, styles all believers "brethren," "saints," a "spiritual temple," a "peculiar people," a "holy and royal priesthood." It is remarkable, that Peter in particular should present the idea of the priesthood as the destiny of all, and apply the term clerus not to the ministerial order as distinct from the laity, but to the community; thus regarding every Christian congregation as a spiritual tribe of Levi, a peculiar people, holy to the Lord. 
The temporal organization of the empirical church is to be a means (and not a hindrance, as it often is) for the actualization of the ideal republic of God when all Christians shall be prophets, priests, and kings, and fill all time and all space with his praise.
1. Bishop Lightfoot begins his valuable discussion on the Christian ministry (p.179) with this broad and liberal statement: "The kingdom of Christ, not being a kingdom of this world, is not limited by the restrictions which fetter other societies, political or religious. It is in the fullest sense free, comprehensive, universal. It displays this character, not only in the acceptance of all comers who seek admission, irrespective of race or caste or sex, but also in the instruction and treatment of those who are already its members. It has no sacred days or seasons, no special sanctuaries, because every time and every place alike are holy. Above all it has no sacerdotal system. It interposes no sacrificial tribe or class between God and man, by whose intervention alone God is reconciled and man forgiven. Each individual member holds personal communion with the Divine Head. To Him immediately he is responsible, and from Him directly he obtains pardon and draws strength."
But he immediately proceeds to qualify this statement, and says that this is simply the ideal view -- "a holy season extending the whole year round, a temple confined only by the limits of the habitable world, a priesthood co-extensive with the race" -- and that the Church of Christ can no more hold together without officers, rules, and institutions than any other society of men. "As appointed days and set places are indispensable to her efficiency, so also the Church could not fulfil the purposes for which she exists without rulers and teachers, without a ministry of reconciliation, in short, without an order of men who may in some sense be designated a priesthood. In this respect the ethics of Christianity present an analogy to the politics. Here also the ideal conception and the actual realization are incommensurate and in a manner contradictory."
2. Nearly all denominations appeal for their church polity to the New Testament, with about equal right and equal wrong: the Romanists to the primacy of Peter; the Irvingites to the apostles and prophets and evangelists, and the miraculous gifts; the Episcopalians to the bishops, the angels, and James of Jerusalem; the Presbyterians to the presbyters and their identity with the bishops; the Congregationalists to the independence of the local congregations and the absence of centralization. The most that can be said is, that the apostolic age contains fruitful germs for various ecclesiastical organizations subsequently developed, but none of them can claim divine authority except for the gospel ministry, which is common to all. Dean Stanley asserts that no existing church can find any pattern or platform of its government in the first century, and thus strongly contrasts the apostolic and post-apostolic organizations (l.c.): "It is certain that the officers of the apostolical or of any subsequent church, were not part of the original institution of the Founder of our religion; that of Bishop, Presbyter, and Deacon; of Metropolitan, Patriarch, and Pope, there is not the shadow of a trace in the four Gospels. It is certain that they arose gradually out of the preexisting institutions either of the Jewish synagogue, or of the Roman empire, or of the Greek municipalities, or under the pressure of local emergencies. It is certain that throughout the first century, and for the first years of the second, that is, through the later chapters of the Acts, the Apostolical Epistles, and the writings of Clement and Hermas. Bishop and Presbyter were convertible terms, and that the body of men so-called were the rulers -- so far as any permanent rulers existed -- of the early church. It is certain that, as the necessities of the time demanded, first at Jerusalem, then in Asia Minor, the elevation of one Presbyter above the rest by the almost universal law, which even in republics engenders a monarchial element, the word 'Bishop' gradually changed its meaning, and by the middle of the second century became restricted to the chief Presbyter of the locality. It is certain that in no instance were the apostles called 'Bishops' in any other sense than they were equally called 'Presbyters' and 'Deacons.' It is certain that in no instance before the beginning of the third century the title or function of the Pagan or Jewish priesthood is applied to the Christian pastors .... It is as sure that nothing like modern Episcopacy existed before the close of the first century as it is that nothing like modern Presbyterianism existed after the beginning of the second. That which was once the Gordian knot of theologians has at least in this instance been untied, not by the sword of persecution, but by the patient unravelment of scholarships."
 Comp. Matt. 16:18; 18:18; 28:18-20; Mark 16:15; Luke 22:19; John 20:21-23; Eph. 2:20 ff.; 4:11 ff.  2:Cor. 2:16.  Acts 20:28.  Acts 6:6; 1:Tim. 4:14; 5:22; 2:Tim. 1:6.  Pet. 2:5, 9; 5:3; comp. Rev. 1:6; 5:10; 20:6. The English "priest" (the German Priester) is etymologically a harmless contraction of "presbyter" (i.e., elder), but has become a synonyms for the Latin sacerdos(hiereus, vchk ),meaning an offerer of sacrifices and a mediator between God and the people. Milton said rather sarcastically, "presbyter is priest writ large."
 2:Cor. 2:16.
 Acts 20:28.
 Acts 6:6; 1:Tim. 4:14; 5:22; 2:Tim. 1:6.
 Pet. 2:5, 9; 5:3; comp. Rev. 1:6; 5:10; 20:6. The English "priest" (the German Priester) is etymologically a harmless contraction of "presbyter" (i.e., elder), but has become a synonyms for the Latin sacerdos(hiereus, vchk ),meaning an offerer of sacrifices and a mediator between God and the people. Milton said rather sarcastically, "presbyter is priest writ large."