§ 78. Canonical Practice
In keeping with the fundamental standpoint of the Church on the question of the ordination of those of another faith, as just set forth, both the canons and the practice of the Church speak. The 68th Apostolic canon condemns a bishop, presbyter or deacon who receives ordination a second time, and adds: “except it be proven that he received ordination from a heretic; for those baptized or ordained by such can be neither believers nor clergy.”[1] Basil the Great points to, as the first reason why the church services of heretics need not be recognized, the fact that among them the lawful hierarchical succession has been cut off, so that among them there is no lawful priesthood either.[2] On this basis the Church has, in general, judged the priesthood of all religious societies that were not in communion with the universal Church, paying attention as well to how far those societies had departed from the fundamental truths of the Christian Church; and priests from those societies in which the apostolic succession had been preserved, and which had not erred against the fundamental Christian truths, she received into her communion as regular priests without a new ordination,[3] whereas priests of those societies in which none of this held true she received as mere laymen.[4] Likewise she received as mere laymen those priests too who, though not belonging to any heretical society, had been appointed by bishops who had broken the bond with the lawful hierarchy.[5]
The present-day practice of the Orthodox Church on this question differs as regards the clergy of the Roman Catholic Church from that as regards the Protestants. Among the Protestants the priesthood is not recognized as a divine institution, nor the existence of church hierarchy as being of divine right, and accordingly, apart from everything else, the Orthodox Church cannot recognize, nor does she recognize as priests, those persons among the Protestants who perform religious services among them. As regards the priesthood of the Roman Catholic Church, the Orthodox Church is guided by the 1st canon of the Council of Constantinople of the year 879, at which the lawfulness of that priesthood was recognized;[6] and today, when a Roman Catholic priest wishes to pass over into the Orthodox Church and to be a priest within her, he is received according to the established rite, nor is any rite of ordination performed over him, but the ordination he received in the Roman Catholic Church is recognized.[7]