I have already observed, that the knowledge of the Christian mysteries was, in those times, accounted as a privilege, to be eagerly coveted. It was not likely, then, that reception of them would be accounted a test; which implies a concession on the part of the recipient, not an advantage. The idea of disbelieving, or criticizing the great doctrines of the faith, from the nature of the case, would scarcely occur to the primitive Christians. These doctrines were the subject of an Apostolical Tradition; they were the very truths which had been lately revealed to mankind. They had been committed to the Church's keeping, and were dispensed by her to those who sought them, as a favour. They were facts, not opinions. To come to the Church was all one with expressing a readiness to receive her teaching; to hesitate to believe, after coming for the sake of believing, would be an inconsistency too rare to require a special provision against the chance of it. It was sufficient to meet the evil as it arose: the power of excommunication and deposition was in the hands of the ecclesiastical authorities, and, as in the case of Paulus, was used impartially. Yet, in the matter of fact, such instances of contumacy were comparatively rare; and the Ante-Nicene heresies were in many instances the innovations of those who had never been in the Church, or who had already been expelled from it.
We have some difficulty in putting ourselves into the situation of Christians in those times, from the circumstance that the Holy Scriptures are now our sole means of satisfying ourselves on points of doctrine. Thus, every one who comes to the Church considers himself entitled to judge and decide individually upon its creed. But in that primitive age, the Apostolical Tradition, that is, the Creed, was practically the chief source of instruction, especially considering the obscurities of Scripture; and being withdrawn from public view, it could not be subjected to the degradation of a comparison, on the part of inquirers and half-Christians, with those written documents which are vouchsafed to us from the same inspired authorities. As for the baptized and incorporate members of the Church, they of course had the privilege of comparing the written and the oral tradition, and might exercise it as profitably as in comparing and harmonizing Scripture with itself.
Arians of the Fourth Century