'The Assyrian came down like a wolf on the fold,' and Sennacherib and all his army were, by the blast of the breath of His nostrils, swept into swift destruction. The reasons for that historical reference may be briefly stated. We find, for instance, a number of remarkable correspondences between these three psalms and portions of the Book of the prophet Isaiah, who, as we know, lived in the period of that deliverance. The comparison, for example, which is here drawn with such lofty, poetic force between the quiet river which 'makes glad the city of God,' and the tumultuous billows of the troubled sea, which shakes the mountain and moves the earth, is drawn by Isaiah in regard to the Assyrian invasion, when he speaks of Israel refusing 'the waters of Shiloah, which go softly,' and, therefore, having brought upon them the waters of the river--the power of Assyria--'which shall fill the breadth of Thy land, O Immanuel!' Notice, too, that the very same consolation which was given to Isaiah, by the revelation of that significant appellation, 'Immanuel, God with us,' appears in this psalm as a kind of refrain, and is the foundation of all its confident gladness, 'The Lord of Hosts is with us.' Besides these obvious parallelisms, there are others to which I need not refer, which, taken together, seem to render it at least probable that we have in this psalm the devotional echo of the great deliverance of Israel from Assyria in the time of Hezekiah. Now, these verses are the cardinal central portion of the song. We may call them The Hymn of the Defence and Deliverance of the City of God. We cannot expect to find in poetry the same kind of logical accuracy in the process of thought which we require in treatises; but the lofty emotion of devout song obeys laws of its own: and it is well to surrender ourselves to the flow, and to try to see with the Psalmist's eyes for a moment his sources of consolation and strength. I take the four points which seem to be the main turning-points of these verses--first, the gladdening river; second, the indwelling Helper; third, the conquering voice; and fourth, the alliance of ourselves by faith with the safe dwellers in the city of God. I. First, we have the gladdening river--an emblem of many great and joyous truths.