Those who preside over the government of the Church, according to the institution of Christ, are named by Paul, first, Apostles; secondly, Prophets; thirdly, Evangelists; fourthly, Pastors; and, lastly, Teachers (Eph 4:11). Of these, only the two last have an ordinary office in the Church. The Lord raised up the other three at the beginning of his kingdom, and still occasionally raises them up when the necessity of the times requires.
Next come Pastors and Teachers, with whom the Church never can dispense, and between whom, I think, there is this difference, that teachers preside not over discipline, or the administration of the sacraments, or admonitions, or exhortations, but the interpretation of Scripture only, in order that pure and sound doctrine may be maintained among believers. But all these are embraced in the pastoral office.