“III. The title to the exercise of the ministerial office is, in ordinary circumstances, conferred by Christ through the call of the Church.
There is a distinction, and a most important one in the argument, to be drawn between the title to the possession of the ministerial office, and the title to the exercise of the ministerial office. The former, or the right to the office, is the gift immediately of Christ; His call, directly addressed to the individual, gives him this first right. The latter, or the right to the exercise of the office, is also the gift of Christ; not, however, immediately or directly bestowed, but conferred through the regular and outward appointment of the Church.
The first, or a right to the ministerial office, is one involved in the call of the Saviour Himself, addressed and announced to the individual by the bestowment upon him of those special gifts and graces of a spiritual kind which alone can qualify him for the office. The second, or a right to the exercise of the office, is involved in the call of the Church, when, by ordination and regular investiture, he is outwardly set apart to the discharge of the duties connected with the office. The warrant both to possess and exercise the office is complete only then when he has received both the direct call of Christ and the outward call of the Church. The one of these, or the inward call addressed to him from His Lord in heaven, gives a warrant and title to the possession of the ministerial office; and that title is made good to the effect of conferring the right—not to the possession, but over and above that—to the exercise of the ministerial office, when it is recognized by the Church as coming from its Divine Head, and when the Church, in deference to His choice thus intimated, proceeds to give the outward call, and by ordination solemnly to set apart the individual so chosen to the office of the ministry. The distinction of the old divines, formerly adopted in regard to the residence of Church power, is the very distinction to be adopted in the case before us of a right to the ministerial office. That right may be regarded as existing ‘in esse,’ and it may be regarded as existing ‘in operari;’ and in all ordinary cases the one of these must supplement the other before a man is entitled to assume the power of discharging the duties of the ministry. The right ‘in esse’ is conferred immediately by the call of Christ, expressed to the individual through the bestowment on him of the special gifts and graces suitable for office. The right ‘in operari’ is conferred by Christ too, but in ordinary circumstances only through the call of the Church to the same individual, recognizing in him the choice of Christ, and proceeding, by the solemn act of ordination, to set him apart to the office of the ministry. Until this formal and outward call of the Church is superadded to the inward call of Christ, the individual’s title to the ministerial office, both for the possession of it and for the exercise of it, is not, in ordinary circumstances, complete.
I do not stop at present, because I shall refer to it afterwards, to inquire what extraordinary circumstances may justify or demand. But on all ordinary occasions, the right to the ministerial office ‘in esse’ and the right to it ‘in operari’ must be conjoined; and the call of Christ and the call of the Church must unite before a man is justified in entering upon the work of the ministry. The outward investiture by ecclesiastical ordination is needful for the work of the ministry besides the call, inward and sovereign, of Christ to the office of the ministry. The one ought to be added to the other before a man may regularly enter upon ecclesiastical duties in the Church.
That in ordinary circumstances a minister ought to be ordained to his office by those who have been in office before, is an assertion which is justified both by Scripture injunction and Scripture example. The practice of ordination, through which an individual is admitted to the exercise of the ministry, is one very distinctly sanctioned and required by apostolic authority. The imposition of hands by the office-bearers of the Church was not a mere empty and unmeaning ceremony, but the last and crowning act by which the previous call of Christ to the individual was recognized and given practical effect to , and he was set apart to the work of the ministry.”
-From Church of Christ—Volume I, by James Bannerman (Students Reformed Theological Library; Banner of Truth Trust—Edinburgh) First Published 1869 Pages 430-431.