Whoever attempts a close investigation of the nature of positive institutions, will find that the line of separation between them and moral duties, is not always so easy to be drawn as might at first be imagined. We say, indeed, that the former are not discoverable by the light of nature. The reason of that, however, may be, not because they do not in reality originate in the nature of things, but merely because, our powers of discovery are so feeble. Were these powers expanded, and the range of our intellectual vision widened, we might possibly see that those very institutions we call positive, grow naturally and necessarily out of the relation between God and us. Not only might we see the reasons of positive institutions in general, (which indeed is already sufficiently obvious,) but with such enlarged capacities, we might see the reason why such particular ones are pitched upon rather than others. The real difference between moral and positive duties may, after all, be nothing more than this, that the former we can readily discover for ourselves, narrow as the range of our vision is--while the latter, we are so short-sighted, we cannot discover, and are therefore wholly dependent on revelation for them. Hence we suppose it is assuming more than can be proved, when it is argued that positive appointments are altogether arbitrary, and have no real foundation in the nature and fitness of things.[7] Now when we admit that the Sabbath is a positive institution, we mean that it is not discoverable by the light of nature, but is purely a matter of revelation; and this is all we mean. It still possesses the main attributes of a moral precept. For as we have already shown, any duty which has its origin in the natural relation of creature to Creator, must be of a moral nature, whether we can discover it for ourselves, or whether by reason of our short-sightedness, we are altogether dependent on revelation for it. That such is the origin of the Sabbath law, is plain from the most casual inspection of it. It grew out of God's creating the world in six days, and resting on the seventh, and is a constant memorial of it. Besides, it provides for the performance of the worship of God, which is confessedly a moral duty; while the satisfaction it yields to the conscience of every man, is a sufficient indication of its parity with other moral precepts.[8]