The historical substratum for vv. 3, 4, is the twin miracles of drying up the Red Sea and the Jordan, which began and closed the Exodus, and the "quaking" of Sinai at the Theophany accompanying the giving of the Law. These physical facts are imaginatively conceived as the effects of panic produced by some dread vision; and the psalmist heightens his representation by leaving unnamed the sight which dried the sea, and shook the steadfast granite cliffs. In the third pair of verses he changes his point of view from that of narrator to that of a wondering spectator, and asks what terrible thing, unseen by him, strikes such awe? All is silent now, and the wonders long since past. The sea rolls its waters again over the place where Pharaoh's host lie. Jordan rushes down its steep valley as of old, the savage peaks of Sinai know no tremors;--but these momentary wonders proclaimed an eternal truth.
So the psalmist answers his own question, and goes beyond it in summoning the whole earth to tremble, as sea, river, and mountain had done, for the same Vision before which they had shrunk is present to all Nature. Now the psalmist can peal forth the Name of Him, the sight of whom wrought these wonders. It is "the Lord," the Sovereign Ruler, whose omnipotence and plastic power over all creatures were shown when His touch made rock and flint forget their solidity and become fluid, even as His will made the waves solid as a wall, and His presence shook Sinai. He is still Lord of Nature. And, more blessed still, the Lord of Nature is the God of Jacob. Both these names were magnified in the two miracles (which, like those named in ver. 3, are a pair) of giving drink to the thirsty pilgrims. With that thought of omnipotence blended with gracious care, the singer ceases. He has said enough to breed faith and hearten courage, and he drops his harp without a formal close. The effect is all the greater, though some critics prosaically insist that the text is defective and put a row or two of asterisks at the end of ver. 8, "since it is not discernible what purpose the representation [_i.e._, the whole psalm] is to serve" (Graetz)!