GOD’S prophets were his witnesses to his church, each in his day, for several ages, witnesses for him and his authority, witnesses against sin and sinners, attesting the true intents of God’s providences in his dealings with his people then and the kind intentions of his grace concerning his church in the days of the Messiah, to whom all the prophets bore witness, for they all agreed in their testimony; and now we have only one witness more to call, and we have done with our evidence; and though he be the last, and in him prophecy ceased, yet the Spirit of prophecy shines as clearly, as strongly, as brightly in him as in any that went before, and his testimony challenges an equal regard. The Jews say, Prophecy continued forty years under the second temple, and this prophet they call the seal of prophecy, because in him the series or succession of prophets broke off and came to a period. God wisely ordered it so that divine inspiration should cease for some ages before the coming of the Messiah, that that great prophet might appear the more conspicuous and distinguishable and be the more welcome. Let us consider,
I. The person of the prophet. We have only his name, Malachi, and no account of his country or parentage. Malachi signifies my angel, which has given occasion for a conjecture that this prophet was indeed an angel from heaven and not a man, as that Judges ii. 1. But there is no just ground for the conjecture. Prophets were messengers, God’s messengers; this prophet was so; his name is the very same with that which we find in the original (ch. iii. 1) for my messenger; and perhaps from that word he might (though, probably, he had another name) be called Malachi. The Chaldee paraphrase, and some of the Jews, suggest that Malachi was the same with Ezra; but that also is groundless. Ezra was a scribe, but we never read that he was a prophet. Others, yet further from probability, make him to be Mordecai. But we have reason to conclude he was a person whose proper name was that by which he is here called; the tradition of some of the ancients is that he was of the tribe of Zebulun, and that he died young.
II. The scope of the prophecy. Haggai and Zechariah were sent to reprove the people for delaying to build the temple; Malachi was sent to reprove them for the neglect of it when it was built, and for their profanation of the temple-service (for from idolatry and superstition they ran into the other extreme of impiety and irreligion), and the sins he witnesses against are the same that we find complained of in Nehemiah’s time, with whom, it is probable, he was contemporary. And now that prophecy was to cease he speaks more clearly of the Messiah, as nigh at hand, than any other of the prophets had done, and concludes with a direction to the people of God to keep in remembrance the law of Moses, while they were in expectation of the gospel of Christ.
– Matthew Henry Commentary