It is moreover in incidental passages of the Scriptures, in which the methods of business are commended to the searchers after higher things, that we see their high estimate of those methods and gains. "_Buy the truth, and sell it not; buy wisdom and understanding_" (Prov. xxiii, 23). "_Buying up for yourselves opportunities_" (Col. iv, 5). "_I counsel thee to buy of me gold refined by fire, that thou mayest be rich; and white garments, that thou mayest be clothed; and eye-salve to anoint thine eyes, that thou mayest see_" (Rev. iii, 18). "_But rather let him labor, working with his hands at that which is good, that he may have to give to him that is in need_" (Eph. iv, 28). "_But if any one provideth not for his own, and especially for those of his own house, he hath denied the faith, and is worse than an unbeliever_" (1 Tim. v, 8). Now, the universal test and proof of any truth is its harmony with some other truths. Does an alleged truth fall in with and fill out well some other demonstrated and accepted proposition, or a number of such other propositions? If so, then that truth is _proved_. Human reason can no further go. The mind rests with relish and content in a new acquisition. To apply this to the case in hand,--if men were designed of their Maker to buy and sell to their own mutual benefit and advancement, if mankind have always been buying and selling as towards that end and with that obvious result, and if the Future promises to increase and reduplicate the buying and selling of the Present in every direction without end, and all in the interest of a broad civilization and a true and lasting progress; and if, in harmony with these truths, the written revelation of God in every part of it assumes that buying and selling in its inmost substance and essential forms be good and righteous and progressive, and suitable in all its ends and methods to illustrate and enforce ends and methods in the higher kingdom of spiritual and eternal Life;--then these coördinate truths will logically and certainly follow, (1) that Trade is natural and essential and beneficial to mankind; (2) that it constitutes in an important sense a realm of human thought and action by itself, separate from the neighboring realm of Giving, and equally from the hostile realm of Stealing; and (3) that a careful analysis of what buying and selling in its own peculiar nature is, a thorough ascertainment and a consequent clear statement of its fundamental laws, and a faithful exposure of what in individual selfishness and in subtle or open Legislation makes against these laws, _must be of large consequence to the welfare of mankind_.