Turn again our captivity, O Lord - literally, “Turn our captivity.” The word “again” is inserted by the translators, and conveys an idea which is not necessarily in the original. It is simply a prayer that God would “turn” their captivity; that is, looking upon the captivity as not wholly ended, or as, in some sense, still continuing, that it might please him wholly to turn it, or to end it. The language would be applicable, if there was a new “captivity” similar to the one from which they had been delivered, or if the one mainly referred to was not complete; that is, if a part of the people still remained in bondage. The latter is probably the idea, that while a considerable part of the nation had been restored, and while an order had been issued for the restoration of all the captives to their native land, it was still true that a portion of them remained in exile; and the prayer is, that God would interfere in their behalf, and complete the work. A portion of the exiles, in fact, returned under Cyrus; a part under Darius; a part under Xerxes and his successors. The return was by no means accomplished at once, but occupied a succession of years.
As the streams in the south - In the southern parts of Palestine, or in the regions bordering it on the south - Idumea and Arabia. That is, As those streams when dried up by the summer heat are swelled by autumnal and winter rains, so let the streams of the returning people, which seem now to be diminished, be swelled by augmenting numbers coming again to their own land. Let the companies of returning emigrants be kept full, like swollen streams, until all shall have been brought back.