The reference is to a seal-ring, and the promise is that God will preserve Zerubbabel from all the assaults of the wicked.  Zerubbabel was one of the Messiah’s ancestors (Matt. 1:12; Luke 3:27), and since the prophecy reached far beyond his day, the promise made to him extends to all faithful rulers whom God sets over his church but can have its perfect fulfilment only in the Messiah himself, of whom Zerubbabel was a type.

XI.  ZECHARIAH.

20.  Zechariah, the second and greatest prophet of the Restoration, calls himself the son of Berechiah, the son of Iddo (1:1).  But in Ezra the name of the father is omitted, perhaps as being less known, and he is called simply the son of Iddo (chaps. 5:1; 6:14), the word son being used in the general sense of descendant.  There is no reason to doubt the identity of this Iddo with the priest of that name who went up from Babylon with Zerubbabel and Jeshua (Neh. 12:4); so that Zechariah, like Jeremiah and Ezekiel, was of priestly descent.  He began to prophesy two months after Haggai (chap. 1:1 compared with Hag. 1:1), and the two prophets were contemporary, at least for a short time.

21.  The book of Zechariah may be naturally divided, according to its contents, into three parts.  The first six chapters constitute the first of these parts.  After a short introductory message (1:1-6) there follows a very remarkable series of visions relating to the reestablishment of the Jews in their own land, and the future dispensations of God towards them; the whole being closed by a symbolic prophecy of Christ as both priest and king upon the throne of David.  To the second part belong the prophecies contained in the seventh and eighth chapters.  The occasion of the first of these was a question proposed to the prophet concerning the observance of a certain fast.  He first rebukes the people for their formality, and then proceeds to encourage them in the way of duty, adding glorious promises respecting the future prosperity of Judah and Jerusalem.  The remaining six chapters, constituting the third part, appear to have been written at a later time.  They all relate to the future destinies of the covenant people, and, through them, of the visible kingdom of God on earth.  But the first three of these chapters are mainly occupied with the nearer future, yet with glimpses at the final consummation in the latter days.  They are generally understood to predict the conquests of Alexander the Great (9:1-8), the conflict of the Jews with their enemies in the Maccabean age (9:13-16), the advent of Christ (9:9), the corrupt and rapacious character of the Jewish rulers at that era, their rejection of Christ, and the consequent rejection of the nation by God (chap. 11).  They also contain a prediction of the final reunion and restoration of “the house of Judah” and “the house of Joseph” (ch. 10).  The remaining three chapters are occupied with the great and decisive conflict of the last days, which is to usher in the era of millennial glory.