Psalm 137 refers, and alone does to give the full history of Israel's sorrows to Babylon, which has only a mystic fulfillment in the latter days, but has its importance, because at that time was the closing of the period of the divine presence in Jerusalem, and the setting up of the power of the Gentiles. But faith could not content itself in a strange land nor sing the Lord's songs there; for they were not a heavenly peoplehence they turn to Jerusalem, which faith never forgets. Babylon is to be destroyed and her judgment is desired; Edom's enmity not forgotten. The object of the psalm is to bring out their attachment to Zion in their captivity; there was no separation of heart from it in the strange land.