It is a serious article of belief with the Protestant group of churches, that not merely in a general way, but for every single individual during his earthly life, Christianity is to be realized through a “church”; this “church” stands for the continuous visible embodiment of Christianity, and accordingly it receives the individual into its constituency as a mere unit in the totality, in order that it may furnish him a safe passage through the judgment that shall finally take place on all the deeds of men. And this does not prevent many men, in all the Christian communions, from believing that membership in these communions is the chief matter; and they busy themselves about the fundamental conditions of such a membership only for a couple of hours on Sundays. This accounts for the title of this chapter. For we are going to ask, not what belongs dogmatically to the Christian doctrine, but what kind of preliminary dispositions are required in the human intellect and will before we can accept and understand the teachings of Christianity. In this sense they are “prolegomena.” If some reader, after going through this chapter, should say that the very substance of Christianity itself lies therein, I shall not disturb him in his conception; for his conception would at any rate do him less harm than the other view, which would declare these preliminaries to be too difficult, or not necessary, for entrance into the church of Christ. These first steps are quite easily outlined in a few words: first, to regard God as an actual existence and not as a mere philosophical idea of the schools,--and then, in consequence, to fear him alone and to serve him alone--to have no other idols beside him, neither men, nor possessions, nor glory; secondly, to love the men among whom one is placed “as oneself,” as Christ says, in practical words we can understand--not often more than oneself apparently, and as a matter of fact, in most cases less; thirdly, not to devote one’s life to pleasure even of the so-called “noblest” sorts, nor, on the other hand, to suffering, to mere asceticism,--but to surrender oneself to the doing of the will of God, in the firm confidence that this must be practicable, though not through one’s own moral power, yet through the divine help and grace; and, fourthly, if any one should at first doubt whether all this is possible for man, to believe that, so far as concerns himself, the matter lies only in his _will_, the only thing he can, but must, contribute thereto. These are the “prolegomena” of Christianity which every one must consider, before he resolves, upon reaching his years of discretion, to make a real entrance into the Christian life, instead of going forward upon the broader way, easier at the first, but sure to be unsatisfactory in the end.