One thing is certain--according to ancient prophecy, and agreeable to the general expectation of this and other ages, the day approaches which will flood the earth with the pure principles of religious knowledge; a day when none will have to teach his neighbour, saying, Know ye the Lord; for all persons shall know Him, from the least to the greatest. It should be a matter of serious thought and investigation--without respect to party, sect, or creed, whether there should not, in the very nature of present circumstances, and future Millennial hopes, be an entire remodelling, or re-organization of religious society, upon the broad basis of revealed knowledge, tangible fact, and philosophical, scientific and spiritual Truth--a universal "_standard_," of immutable Truth, instead of numberless systems founded on uncertainty, opinion, mere human impression, or conjecture. Can anything short of such a standard unite society, enlighten the world, establish real peace, brotherhood and fellowship, and put a final end to all religious ignorance, superstition, jargon, or discord? Is not a difference of opinion, or a disagreement on any given subject, a proof positive of existing ignorance, or want of light or information, on the part of the parties disagreeing? If so, the present age is certainly in the dark, or, in a great measure, ignorant on religious subjects. A knowledge of the Truth can alone bring the desired union, and bid discord cease. If the Scriptures be true, it is not religious _opinion_ which will cover the earth, and universally pervade every bosom, but it is, a KNOWLEDGE, "The knowledge of God." "_God is Truth_." To _know_ Him, is to know the Truth. The present Volume aims to embody, in a concise and somewhat original manner and style, a general view of the Science of Theology, as gathered from revelation, history, prophecy, reason and analogy. If the Work proves an introductory key to some of the first principles of the divine science of which it treats; if it serves to open the eyes of any of his fellowmen, on the facts of the past, the present, and the future; if it leads to investigation and inquiry, and calls public attention to the greater and more particular truths which have been, or are about to be, revealed as a standard by which to unite the people of all nations and of all religions upon the rock, the sure foundation of divine, eternal, uncreated, infinite and exhaustless Truth, it will have accomplished the end aimed at by THE AUTHOR. Key to Theology. CHAPTER I. THEOLOGY--ITS DEFINITION--HISTORICAL ILLUSTRATIONS. Eternal Science! who would fathom thee Must launch his bark upon a shoreless sea. Thy knowledge yet shall overwhelm the earth, Thy truth to immortality to give birth; Thy dawn shall kindle to eternal day, And man, immortal, still shall own thy sway.