Since religious systems, true and false, have one and the same great and comprehensive subject-matter, they necessarily interfere with one another as rivals, both in those points in which they agree together, and in those in which they differ. That Christianity on its rise was in these circumstances of competition and controversy, is sufficiently evident even from a foregoing Chapter: it was surrounded by rites, sects, and philosophies, which contemplated the same questions, sometimes advocated the same truths, and in no slight degree wore the same external appearance. It could not stand still, it could not take its own way, and let them take theirs: they came across its path, and a conflict was inevitable. The very nature of a true philosophy relatively to other systems is to be polemical, eclectic, unitive: Christianity was polemical; it could not but be eclectic; but was it also unitive? Had it the power, while keeping its own identity, of absorbing its antagonists, as Aaron's rod, according to St. Jerome's illustration, devoured the rods of the sorcerers of Egypt? Did it incorporate them into itself, or was it dissolved into them? Did it assimilate them into its own substance, or, keeping its name, was it simply infected by them? In a word, were its developments faithful or corrupt? Nor is this a question merely of the early centuries. When we consider the deep interest of the controversies which Christianity raises, the various characters of mind it has swayed, the range of subjects which it embraces, the many countries it has entered, the deep philosophies it has encountered, the vicissitudes it has undergone, and the length of time through which it has lasted, it requires some assignable explanation, why we should not consider it substantially modified and changed, that is, corrupted, from the first, by the numberless influences to which it has been exposed. 2.