Charles H. Spurgeon on Psalms 78:13

He made the waters to stand as an heap. God did not wish altogether to take the sea from the gaze of the Hebrews, but to interrupt and divide it, that like a wall it might stand firm on either side of the way. This was done, first, that the miracle might be evident, for in that sea there is no tidal rise or fall of the waters. Secondly, that the people might have greater joy at the sight of so great a miracle. Thirdly, that in their whole passage they might depend more upon the providence of God, who, in a single moment, could allow the sea to return to its bed and drown all of them. It is God's will than we should flee to him the more ardently as the aspect of present danger. Fourthly and lastly, that the people might pass over the more rapidly, since they knew not how long God wished the miracle to last. Thomas Le Blanc.