The picture in the psalm is most striking. The continuous short clauses crash and flash like the thunders and lightnings. That energetic metaphor of the waters writhing as if panic-struck is more violent than Western taste approves, but its emotional vigour as a rendering of the fact is unmistakable. "Thine arrows went to and fro" is a very imperfect transcript of the Hebrew, which suggests the swift zigzag of the fierce flashes. In ver. 18 the last word offers some difficulty. It literally means _a wheel_, and is apparently best rendered as above, the thunder being poetically conceived of as the sound of the rolling wheels of God's chariot. There are several coincidences between vv. 16-19 of the psalm and Hab. iii. 10-15: namely, the expression "writhed in pain," applied in Habakkuk to the mountains; the word rendered "overflowing" (A.V.) or "tempest" (R.V.) in Hab. v. 10, cognate with the verb in ver. 17 of the psalm, and there rendered "poured out"; the designation of lightnings as God's arrows. Delitzsch strongly maintains the priority of the psalm; Hupfeld as strongly that of the prophet.
The last verse returns to the two-claused structure of the earlier part. It comes in lovely contrast with the majestic and terrible picture preceding, like the wonderful setting forth of the purpose of the other theophany in Psalm xviii., which was for no higher end than to draw one poor man from the mighty waters. All this pomp of Divine appearance, with lightnings, thunders, a heaving earth, a shrinking sea, had for its end the leading the people of God to their land, as a shepherd does his flock. The image is again an echo of Exod. xv. 13. The thing intended is not merely the passage of the Red Sea, but the whole process of guidance begun there amid the darkness. Such a close is too abrupt to please some commentators. But what more was needful or possible to be said, in a retrospect of God's past acts, for the solace of a dark present? It was more than enough to scatter fears and flash radiance into the gloom which had wrapped the psalmist. He need search no further. He has found what he sought; and so he hushes his song, and gazes in silence on the all-sufficient answer which memory has brought to all his questions and doubts. Nothing could more completely express the living, ever-present worth of the ancient deeds of God than the "abruptness" with which this psalm ceases rather than ends.