4. Another very frequent mistake bearing upon moral character deserves a passing notice here. Men sometimes manifest, and doubtless with a consciousness of inward sincerity, a very high regard for some one or more particular principles of virtue, while they manifest an equal disregard of all other principles. Every real reform, for example, has its basis in some great principle of morality. Men often advocate, with great zeal, such reforms, together with the principle on which they rest. They talk of virtue, when called to defend that principle, of a regard to moral obligation, together with the necessity of self-sacrifice at the shrine of duty, as if respect for universal rectitude commanded the entire powers of their being. Yet but a slight observation will most clearly evince, that their regard for the right, the true, and the good, is wholly circumscribed by this one principle. Still, such persons are very likely to regard themselves as virtuous in a very high degree. In reality, however, they have not made the first approach to real virtue. Their respect for this one principle, together with its specific applications, has its spring in some other department of their nature, than a regard for what is right in itself. Otherwise their respect for what is right, would be co-extensive with the entire range of moral obligation. SEC. II. TEST OF CONFORMITY TO MORAL PRINCIPLE. In preceding chapters, the great truth has been fully established, that the Moral law addresses its commands and prohibitions to the Will only, and that moral obligation is predicable only of the action of the voluntary power, other states being required, only as their existence and character are conditioned on the right exercise of that power. From this, it undeniably follows, that the Moral law, in all the length and breadth of its requirements, finds its entire fulfilment within the sphere of the Will. A question of great importance here presents itself: By what test shall we determine whether the Will is, or is not, in full harmony with the law? In the investigation of this question, we may perhaps be thought to be intruding somewhat into the domain of Moral Philosophy. Reasons of great importance, in the judgment of the writer, however, demand its introduction here. The Moral law is presented to us through two comprehensive precepts. Yet, a moment's reflection will convince us that both these precepts have their basis in one common principle, and are, in reality, the enunciation of that one principle. The identical reason why we are bound to love God with all the heart, requires us to love our neighbors as ourselves. So the subject is presented by our Saviour himself. After speaking of the first and great commandment, He adds, "the second is like unto it," that is, it rests upon the same principle as the first.