Moreover, the revelation by which God makes himself known to man, does not admit of being limited exclusively to the written word. Nature itself is a book written on both sides, both within and without, in every line of which the finger of God is discernible. It is, as it were, a Holy Writ in visible form and bodily shape--a song of praise on the Creator’s omnipotence composed in living imagery. But besides Scripture and nature--those two great witnesses to the greatness and majesty of God--there is in the voice of conscience nothing less than a divine revelation within man. This is the first awakening call to the two other louder and fuller proclamations of revealed truth. And, lastly, in universal history we have set before us a real and manifold application and progressive development of revelation. Here the luminous threads of a divine and higher guidance glimmer through the remarkable events of history. For, not only in the career of whole ages and nations, but also in the lives of individuals, the ruling and benignant hand of Providence is every where visible. Fourfold, consequently, is the source of revelation, from which man derives his knowledge of the Deity, learns his will, and understands his operation and power--conscience, nature, Holy Writ, and universal history. The teaching of the latter is often of that earnest and awful kind, to which we may, in a large sense, apply the adage, “Who will not learn must feel.” How often does it show us some mighty edifice of fortune, which, having no firm basis in the deep soil of truth and the divine order, owed its rapid growth and false splendor to some evil influence, falling suddenly in ruins, as if stricken by the invisible breath of a superior power. On such occasions the public feeling recognizes the hand which sets a limit to every temerity in the history of the world--to every extravagance of a false confidence--and appoints it its ultimate term. And the olden notion (which, with men of the day, had become little more than an antiquated legend) of God’s retributive justice, resumes its place among the actuating sentiments of life, with new and intense significance. The sublime truth, however, is only too soon forgotten, and the temporary alarm subsides but too quickly into the habitual calm of a false security--that old and hereditary feeling of human nature.