Patrick Fairbairn, Prophecy Viewed in Respect to its Distinctive Nature, pp. 289-290, speaking of the prophecies in Daniel pertaining to Christ and his kingdom:
"The arms of the republic," says Gibbon, as if writing the interpretation of this part of the vision, "sometimes vanquished in battle, always victorious in war, advanced with rapid strides to the Euphrates, the Danube, the Rhine, and the ocean; and the images of gold and silver or brass, that might serve to represent the nations and their kings, were successively broken by the iron monarchy of Rome."
David Steele, Notes on the Apocalypse, p. 91, writing on Rev. 8.7:
The infidel historian Gibbon has unwittingly recorded the fulfilment of these prophecies, as Josephus has done those of our Lord respecting the destruction of Jerusalem. Unconscious that he was bearing testimony to the truth of prophecy, Gibbon used with his classic pen the very allegorical language of the inspired apostle. Respecting the incursion of the barbarous Goths, as led by Alaric their chief into the fertile plains of southern Europe, he describes their alarming descent as a "dark cloud, which having collected along the coasts of the Baltic, burst in thunder upon the banks of the upper Danube." He who directed Balaam and Caiaphas to utter predictions, doubtless could direct Josephus and Gibbon to attest the truth of prophecy; and this may be one of the many ways in which "he makes the wrath of man to praise him."
John Cumming, Prophetic Studies: Lectures on the Book of Daniel, pp. 77-79:
But the most decisive testimony to the universal iron supremacy of Rome, the fourth empire of Daniel, is given by Gibbon, who, as usual, is here the undesigning, the unconscious, but the faithful witness to the truth of the prophecies of God. Gibbon thus speaks of the extent of the Roman dominions: -- "The empire was about two thousand miles in breadth, from the wall of Antoninus and northern limits of Dacia to the Atlas and the tropic of cancer. It extended in length more than three thousand miles, from the Western ocean to the Euphrates. The arms of the republic, sometimes vanquished in battle, always victorious in war, advanced with rapid strides to the Euphrates, and the Danube, and the Rhine, and the ocean ; and the image of gold, or silver, or brass, that might serve to represent the nations or kings, were successively broken by the iron monarchy of Rome."
Thus, strange enough, Gibbon states, as if he could find no language so truly descriptive of historic fact as the language of Daniel, "The image of gold, or silver, or brass, that might serve to represent the nations of kings, was successively broken up by the iron monarchy of Rome;" so completely does God's prophecy find its echo in man's unconscious history. In other words, the infidel historian could find no language so descriptive of fact as the very words of prophecy in the book of Daniel; and thus he proved, not only the fulfilment of prophecy, but the fulness, the beauty, and the force of the words in which that prophecy was couched.
This iron despotism or empire is further proved to be the fourth universal empire, by another extract which I will give from Gibbon. "There was," says the historian, "not an inch of ground then known exempt from its sceptre. The modern tyrant who should find no resistance in his own breast, or in his people, would soon experience a gentle restraint from the example of his equals, the dread of censure, the apprehension of enemies. The object of his displeasure escaping the narrow limits of his dominion, would easily obtain, in a happier climate, a secure refuge, freedom of complaint, and perhaps means of revenge. But the empire of the Romans filled the world, and when that empire fell into, the hands of a single person, the world became a safe and dreary prison for his enemies. To resist was fatal, and it was impossible to fly. On every side he was encompassed with a vast extent of sea and land, which he could never hope to traverse, without being discovered, seized, and restored to his irritated master. Beyond the frontiers, he could discover nothing except the ocean, inhospitable deserts, and hostile tribes of fierce barbarians."
Gibbon is my witness that the fourth kingdom should be "strong as iron; forasmuch as iron breaketh in pieces and subdueth all things, so shall it break in pieces and bruise." Thus truly is history the echo of prophecy! God sketches the outline in his word, and kings, and heroes, and poets, and painters, and historians, as if smitten with some mysterious instinct, instantly rise to their places, and fill up with their details what God has so fully sketched.
John Cox Boyce, Nigh Unto the End: or, A Passage in Sacred Prophecy (Rev. xvi. 12-15), pp. 50-52:
The pages of Gibbon ('Decline and Fall of the Roman Empire') give, incidentally, valuable, though perfectly involuntary testimony to the remarkable manner in which the Turks have fulfilled, both in their own persons, and in their demeanour towards others, the sacred prophet's inspired utterances. Their fierceness of countenance and conduct has long since passed into the proverb -- 'As fierce as a Turk.' That they 'destroyed wonderfully' is repeatedly borne witness to by Gibbon. Witness the very first sentence in the chapter (vol. xii. p. 182) in which he describes the siege of Constantinople by the Turks -- as attracting, he says, 'our first attention to the person and character of the great destroyer.' When the reader remembers that the Sultan, in virtue of his office, and with the sanction of his religion, is at liberty to put to death, without responsibility, a certain number of his subjects daily—a prerogative by no means abandoned in modern times—he will see, in this fact alone, to what revolting deeds, which are plentifully chronicled on the historic page, his fierceness of nature would be likely to prompt him. The very Koran itself demands of him, in order that he should be true and faithful to it, the utmost cruelty—even to extermination—against the ' dogs,' or Christians. The words of Gibbon, again—infidel though he was—strikingly illustrate the truth of Daniel's prediction in this particular, when he says, with reference to Mahomet II., the Conqueror of Constantinople—'His passions were at once furious and inexorable: in the palace, as in the field, a torrent of blood was spilt on the slightest provocation' (xii. p. 185.) Daniel was led by the angel to see that the power destined to darken, in so grievous a manner, the records of future history, ' by his policy would cause craft to prosper in his hand.' And that such is the policy of the Turk—a policy to which he is bound by his religion—a policy that renders inexcusable the conduct of those statesmen in these modern times, who would not extort from him the most stringent guarantees for the performance of his promises, is thus borne witness to by Gibbon (xii. 187)—'The Mahometan, and more especially the Turkish casuists, have pronounced that no promise can bind the faithful against the interest and duty of their religion; and that the Sultan may abrogate his own treaties, and those of his predecessors.' 'By peace he shall destroy many,' is another characteristic of the Turk, and here again, who can fail to be struck by Gibbon's appropriate, though, of course, unconscious testimony to the existence of this trait in the character of the Conqueror of Constantinople—'Peace was on his lips, while war was in his heart.' (Ibid., p. 187.)