There are two events, one or other of which probably supplies the historical basis of this and the two following psalms. One is Jehoshaphat's deliverance from the combined forces of the bordering nations (2 Chron. xx.). Delitzsch adopts this as the occasion of the psalm. But the other more usually accepted reference to the destruction of Sennacherib's army is more probable. Psalms xlvi. and xlviii. have remarkable parallelisms with Isaiah. The noble contrast of the quiet river which makes glad the city of God with a tossing, earth-shaking sea resembles the prophet's threatening that the effect of refusing the "waters of Shiloah which go softly" would be inundation by the strong and mighty river, the Assyrian power. And the emblem is expanded in the striking language of Isa. xxxiii. 21: "The glorious Lord will be unto us a place of broad rivers and streams; wherein shall go no galley with oars." Encircled by the flashing links of that broad moat, Jerusalem sits secure. Again, the central thought of the refrain in the psalm, "The Lord of hosts is with us," is closely allied to the symbolic name which Isaiah gave as a pledge of deliverance, "Immanuel, God with us." The structure is simple. The three strophes into which the psalm falls set forth substantially the same thought, that God's presence is safety and peace, whatever storms may roar. This general theme is exhibited in the first strophe (vv. 1-3) in reference to natural convulsions; in the second (vv. 4-7) in reference to the rage of hostile kingdoms; and in the third (vv. 8-11) men are summoned to behold a recent example of God's delivering might, which establishes the truth of the preceding utterances and has occasioned the psalm. The grand refrain which closes the second and third strophes should probably be restored at the end of ver. 3. In the first strophe the psalmist paints chaos come again, by the familiar figures of a changed earth, tottering mountains sinking in the raging sea from which they rose at creation, and a wild ocean with thunderous dash appalling the ear and yeasty foam terrifying the eye, sweeping in triumphant insolence over all the fair earth. It is prosaic to insist on an allegorical meaning for the picture. It is rather a vivid sketch of utter confusion, dashed in with three or four bold strokes, an impossible case supposed in order to bring out the unshaken calm of those who have God for ark in such a deluge. He is not only a sure refuge and stronghold, but one easy of access when troubles come. There is little good in a fortress, however impregnable, if it is so difficult to reach that a fugitive might be slain a hundred times before he was safe in it. But this high tower, which no foe can scale, can be climbed at a thought, and a wish lifts us within its mighty walls. The psalmist speaks a deep truth, verified in the spiritual life of all ages, when he celebrates the refuge of the devout soul as "most readily to be found."