As respects one great division of miraculous agency, it is clear, therefore, that Hume's argument does not apply. The arrow glances past: not so much missing its aim as taking a false one. The _hiatus_ which it supposes, the insulation and incommunicability which it charges upon the miraculous as a capital oversight, was part of the design: such mysterious agencies were _meant_ to be incommunicable, and for the same reason which shuts up each man's consciousness into a silent world of its own--separate and inaccessible to all other consciousnesses. If a communication is thrown open by such agencies between the separate spirit of each man and the supreme Spirit of the universe, then the end is accomplished: and it is part of that end to close this communication against all other cognizance. So far Hume is baffled. The supernatural agency is incommunicable: it ought to be so. That is its perfection. II. But now, as respects the other great order of miracles--viz., the _external_, first of all, we may remark a very important subdivision: miracles, in this sense, subdivide into two most different orders--1st, _Evidential_ miracles, which simply prove Christianity. 2d, _Constituent_ miracles, which, in a partial sense, _are_ Christianity. And, perhaps, it may turn out that Hume's objection, if applicable at all, is here applicable in a separate way and with a varying force. The first class, the evidential miracles, are all those which were performed merely as evidences (whether simply as indications, or as absolute demonstrations) of the divine power which upheld Christianity. The second class, the constituent miracles, are those which constitute a part of Christianity. Two of these are absolutely indispensable to Christianity, and cannot be separated from it even in thought, viz., the miraculous birth of our Saviour, and his miraculous resurrection. The first is essential upon this ground--that unless Christ had united the two natures (divine and human) he could not have made the satisfaction required: not being human, then, indeed, he might have had power to go through the mysterious sufferings of the satisfaction: but how would that have applied to man? It would have been perfect, but how would it have been relevant? Not being divine, then indeed any satisfaction he could make would be relevant: but how would it have been perfect? The mysterious and supernatural birth, therefore, was essential, as a capacitation for the work to be performed; and, on the other hand, the mysterious death and consequences were essential, as the very work itself.