Zephaniah 3:9

For then Or, afterward, as the particle אז seems to signify here, will I turn, or restore, to the people a pure language I will turn them from their idolatries, and other wickedness, (see Zephaniah 3:13,) to glorify me with one mind and one mouth. The same thing is expressed by speaking the language of Canaan, Isaiah 19:18. This promise seems primarily to respect the Jewish captives in Babylon, and to imply that God would, by the captivity, and other methods of his providence, so reform them and wean them from their idolatries and other sins, that they should, upon their return to their own land, all join together to glorify him with one mind and one mouth, and serve him alone in sincerity and truth. And this was accordingly, in a great measure, accomplished. For they never after their restoration worshipped different gods, as they had done before; but all joined, as well those of the ten tribes that returned, as those of Judah and Benjamin, in the worship of Jehovah alone; nor did the nation in general ever afterward fall into gross idolatry. And it is not to be doubted that their morals in general were much more pure when they returned from Babylon, than at the time they were carried thither. It is, however, generally supposed by commentators, that the full accomplishment of this promise is reserved for the latter days, after the conversion of the Jews, and the coming in of the fulness of the Gentiles, when there shall be one Lord, and his name one, Zechariah 14:9. Accordingly the word rendered people in the first clause is in the plural, עמים, peoples, I will restore to the peoples a pure language: an expression which could hardly be intended of the Jews only, but seems evidently to include the Gentiles also. To serve him with one consent Hebrew, with one shoulder; that is, unanimously, and with joint endeavours. The metaphor is taken from beasts drawing together in one yoke, or men setting their shoulders together to one burden.