The fourth kingdom shall be strong as iron, &c. This description agrees well with the Roman empire, and the event answered the prediction; for the Roman was vastly more strong and extensive than any of the preceding three. As iron breaketh and bruiseth all other metals, so this brake and subdued all the former kingdoms. The metal is here different, and consequently likewise the nation must be different from the preceding. For the four metals must signify four different nations; and as the gold signified the Babylonians, the silver the Persians, and the brass the Macedonians, so the iron must necessarily denote some other nation: and it may safely be said, that there is not, and has not been, a nation upon earth, to which this description is applicable, but the Romans. The Romans succeeded to the Macedonians, and therefore, in course, were next to be mentioned. And as the two arms of silver denoted the two kings of the Medes and Persians, so the two legs of iron seem equally to have signified the two Roman consuls. The iron was mixed with clay; and the Romans were defiled with a mixture of barbarous nations. The Roman empire was at length divided into ten lesser kingdoms, answering to the ten toes of the image. These kingdoms retained much of the old Roman strength; so that the kingdom was partly strong and partly broken It subdued Syria, and made the kingdom of the Seleucidæ a Roman province, in the year sixty- five before Christ; it subdued Egypt, and made the kingdom of the Lagidæ a Roman province, in the year thirty before Christ; and, in the fourth century after Christ, it began to be torn in pieces by the incursions of the barbarous nations. Mr. Mede, who was as able and consummate a judge as any in these matters, observes, “That the Roman empire was the fourth kingdom of Daniel, was believed by the church of Israel, both before and in our Saviour's time; received by the disciples of the apostles, and the whole Christian Church, for the first three hundred years, without any known contradiction. And, I confess, having so good a ground in Scripture, it is with me tantum non articulus fidei, little less than an article of faith:” see his Works, book 4. Ephesians 6, p. 735, and Bishop Newton.
Daniel seems to divide this kingdom into three periods. The first is its strongest and flourishing state, which seems to be denoted by the iron legs: the second is the same kingdom, weakened by civil wars and the divided state of the empire, denoted by the feet, which were part of potter's clay, and part of iron; for which reason the prophet tells us the kingdom shall be divided, though there shall be in it something of the strength of iron, because the iron was mixed with the clay: the third is the same empire in a yet further state of declension, during which one part of it was to be absolutely destroyed, denoted by the toes, the extremity of the image, and of consequence the last period of this fourth empire. As the toes of the feet were part of iron and part of clay, so the kingdom shall be partly strong and partly broken That is, one part of this divided empire shall remain, and the other part be entirely destroyed. And as the last period of this kingdom is denoted by the toes, this evidently intimates that the remaining part, which was not broken, should be divided into ten distinct kingdoms or governments. And whereas thou sawest iron mixed with clay, they shall mingle themselves with the seed of men, &c. The conjunction of the Romans with the conquered nations, and afterward with the Goths, Vandals, and other barbarians, who subverted the empire, seems to be here intended: in consequence of which these ten kingdoms became a medley of people, of different nations, laws, and customs. But they shall not cleave one to another Although the kings of the several nations shall try to strengthen themselves by marriage alliances, yet reasons of state, the desire of empire, and the different interests which they pursue, will prove stronger than ties of blood, and often engage them in contentions and wars with each other, and thereby weaken the common strength. As Tacitus observes, “Dominandi cupido cunctis affectibus flagrantior erit:” The lust of ruling will be more powerful than all the affections. “It is especially observable,” says Wintle, “that in the declining state of the Roman empire, intermarriages with the barbarians were frequent and distinguished, as may be learned from the histories of the times; but yet the cement would not hold so as to form any great kingdom, or even to prevent the impending fate of the empire.” But some explain the verse of the commotions and clashings that took place between the secular and ecclesiastical powers, after the kingdom was divided into ten parts, answerable to the ten toes of the image.