If a brazen mirror were found in some remote, uninhabited island, it might be a doubtful matter how it came thither; but if it properly reflected objects, there could be no doubt of its being a real mirror.
The Bible was written with the professed design of being “profitable for reproof;” nor was there ever a book so adapted to the purpose, or so effectual in its operation in disclosing the inward workings of the human mind. Thousands can bear witness from experience, that it is “quick and powerful, sharper than any two-edged sword, piercing even to the dividing asunder of soul and spirit, and a discerner of the thoughts and intents of the heart.” Its entrance into the mind gives light, and light which discovers the works of darkness. Far from flattering the vices of mankind, it charges, without ceremony, every son of Adam with possessing the heart of an apostate. This charge it brings home to the conscience, not only by its pure precepts, and awful threatenings, but oftentimes by the very invitations and promises of mercy, which, while they cheer the heart with lively hope, carry conviction by their import to the very soul. In reading other books you may admire the ingenuity of the writer; but here your attention is turned inward. Read it but seriously, and your heart will answer to its descriptions. It will touch the secret springs of sensibility; and if you have any ingenuousness of mind towards God, the tears of grief, mingled with those of hope and gratitude, will, ere you are aware, trickle from your eyes.
To whatever particular vices you may have been addicted, here you will discover your likeness; and that, not as by a comic representation on the theatre, which, where it reclaims one person by shaming him out of his follies, corrupts a thousand; but in a way that will bring conviction to your bosom.
“Come see a man which told me all things that ever I did: is not this the Christ?” Such was the reasoning of the woman of Samaria; and who could have reasoned better? That which makes manifest must be light. But this reasoning is applicable to other things as well as to the Messiahship of Jesus. No man can forbear saying of that book, that doctrine, or that preaching which tells him all that ever he did, Is not this the truth? The satisfaction afforded by such evidence approaches near to intuitive certainty; it is having the witness in ourselves.
Should it be objected, that though this may satisfy our own minds, yet it can afford no evidence to others; I answer, It is true that they who shun the light cannot be supposed to possess the same evidence of its being what it is, as those who have come to it that their deeds may be made manifest; yet even they, if at all acquainted with the Bible, must be aware that the likenesses which it draws are, in a considerable degree, their own. It is not to serious Christians only that the gospel is a mirror. Many who never look into that perfect law of liberty from choice and delight, so as to be blessed in their work, but only glance at it in a transient and occasional way, yet perceive so much of their own character in it as to be convinced that it is right, and that they are wrong. The secret conviction of thousands who hear the word, and do it not, resembles that of Pharaoh, “The Lord is righteous, and I and my people are wicked.” The impressions of such people, it is true, are frequently short in their duration; like a man who seeth his natural face in a glass, they go away, and straightway forget what manner of persons they are: but the aversion which they discover seriously to resume the subject, places it beyond all reasonable doubt, that, let their hearts be as they may, the Scriptures have commended themselves to their consciences. They have felt the point of this two-edged sword, and are not disposed to renew the encounter. That this is the case not only with nominal Christians, but with great numbers of professed deists, is manifest from the acknowledgments of such men as the Earl of Rochester, and many others who have relented on the near approach of death. This is often a time in which conscience must and will be heard; and, too often for the happiness of surviving acquaintances, it proclaims to the world that the grand source of their hatred to the Bible has been that for which Ahab hated Micaiah—its prophesying no good concerning them.
The Scriptures are a mirror in which we see not only individual characters, our own and others, but the state of things as they move on in the great world. They show us the spring-head whence all the malignant streams of idolatry, atheism, corruption, persecution, war, and every other evil originate; and, by showing us the origin of these destructive maladies, clearly instruct us wherein must consist their cure.
It has already been observed,* that Christian morality is summed up in the love of God and our neighbour, and that these principles, carried to their full extent, would render the world a paradise. But the Scriptures teach us that man is a rebel against his Maker; that his carnal mind is enimity against God, and is not subject to the law of God, neither indeed can be; that instead of loving God, or even man, in the order which is required, men are become “lovers of their own selves,” and neither God nor man is regarded but as they are found necessary to subserve their wishes.
This single principle of human depravity, supposing it to be true, will fully account for all the moral disorders in the world; and the actual existence of those disorders, unless they can be better accounted for, must go to prove the truth of this principle, and, by consequence, of the Christian system which rests upon it.
Excerpt from: The Gospel in its Own Witness, Chapter III.
Fuller, A. G. (1988). The Complete Works of Andrew Fuller: Controversial Publications (J. Belcher, Ed.; Vol. 2, pp. 63–65). Sprinkle Publications.