From what has just been said, it is evident, that Christianity is the only true religion. And if this be the case, and if there be no salvation except through the faith of Christ, all, save Christians, must be living in error.
Again, if a virtuous life be the end proposed by all religions, and if there be no better life than the Christian life, there can be no religion superior to Christianity. Any other religion must be either equal or inferior to it. If other religions be inferior to Christianity, Christianity must be the best; and we are bound to embrace it, and to reject all others as idle and superstitious. But if there be a religion equal to Christianity, it must be the same as Christianity. For, unless it propose to us the same end to be attained, and the same means for the attainment of that end, as Christianity professes, it cannot be called equal; it must be inferior to the Christian creed.
Furthermore, if we know a cause by its effects, and if Christian holiness be the perfection of human life; and, if we see no such effects produced by any other religion, Christianity must be true; the more so, as its effects are so quickly and so easily produced, and as its power appears so marvellously in the conversion of men. Therefore, there can be no danger of erring in rejecting all other creeds, and cleaving to the faith of Christ.
In order, however, to make what we say more clear, we will descend to particulars, and will discuss divers forms of religion. But, as it would be useless to attempt to discuss all the superstitions which have ever existed, we will reduce them to six, viz., heathen philosophy, astrology, idolatry, Judaism, heresy, and Mahometanism. In our analysis of these false religions, we will ignore the different opinions and divisions which have existed amongst philosophers, astrologers, idolaters, and heretics. We will examine their tenets from a general point of view.