Say thou unto them. The prophet shows why he has reminded them of their forefathers' sins and punishment. Saith the Lord of hosts. The expression recurs three times in this verse; it denotes the almightiness and infinite resources of God (see note A in the appendix to Archdeacon Perowne's edition of this prophet).
Its constant repetition, as in Haggai, gives a certain heaviness to the prophet's style. Turn (return) ye unto me. He calls the people to repentance, partly, doubtless, with a view to their taking an active part in rebuilding the temple, thus carrying on the exhortations of Haggai, but also with reference to their general indevotion and laxity which Ezra afterwards had to reprove (see Ezra 9:2).
Saith the Lord of hosts; literally, (it is) the utterance of Jehovah of hosts. This is a more threatening form than the mere "saith" in the other two places in this verse. And I will turn (return) unto you (Malachi 3:7).
God promises his favour on their repentance and better conduct; as Haggai had been commissioned to proclaim a return of fruitful seasons as soon as the people obeyed his word and attended diligently to the work before them (Haggai 2:19).
They were called now to attend to the pure worship of the Lord, as the sole condition of prosperity. It has been well observed that when it is said, "Turn ye unto me," etc; we are reminded of our free will; and when we cry, "Turn us, good Lord, and we shall be turned," we acknowledge the need of God's preventing grace.