Again, the knowledge of revealed truth as a whole, and of the system in which it should be enshrined and perpetuated on the earth among men, was a special gift communicated to the Apostolic Body. They could not propagate a religion without this special gift of understanding what they were to propagate. This was part of their endowment as Apostles, a point in which they were superior to all who should come after them, who would have to continue and hand on that which they had established.[156] Further, from this gift followed the consciousness from the beginning that the revelation made by Christ to His Apostles was complete as to its substance.[157] He was the Teacher whose word was final: they were those whom He _sent_ to convey it to men. Their name expressed their office—_the sent_. They transmitted what they had received. Those who followed, even the greatest who sat in Peter's seat, watched over the maintenance of what the Apostles had transmitted. They were _overseers_. The name of predilection which stands at the head of documents declaring the faith, re-establishing discipline, terminating disputes, is, as it may be, Gregory, Leo, Pius, but always _Bishop_; and the whole plenitude of spiritual power is conveyed in the word "Bishop of the Catholic Church." Since all that we have been so long saying is an illustration of this principle of the Church,—her own divine authority in promulgating her Lord's message,—we need not dwell on it further, but turn at once to a review of those combats which she actually underwent, in order to see how her liberty and spiritual power are manifested during the period of persecution, by the issue of the conflict in which, from the beginning, she was engaged with various enemies. The first of these conflicts is with unbelieving Judaism, and its period is chiefly from the Day of Pentecost to the destruction of the temple and city of Jerusalem by Roman arms.