5 In the first place, what means, “Perchance our soul has passed over”?. Understand however the meaning to be this: “Do you think our soul has passed over?” and why do they say, “Do you think”? Because the greatness of the danger makes it hardly credible that he has escaped. They have endured a great death: they have been in great dangers; they have been so much oppressed, that they almost gave consent while alive, and were all but swallowed up alive: now therefore that they have escaped, now that they are secure, but still remember the danger, the great danger, say, “Do you think our soul has passed over the water without substance?”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)