The Exodus is the type of the deliverance of God's people. Thou didst walk through (didst tread) the sea with thine horses; literally, thou treadest the sea, thy horses, the horses being explanatory. The prophet takes his imagery from Exodus 15:1-19. He represents God as a warrior in his chariot, leading the way through the waters to the destruction of his enemies and to the salvation of his own people. Through the heap of great waters; or, upon the surge of mighty waters. The verse may also be rendered, Thou treadest the sea—thy horses (tread) the heap of great waters (Psalms 77:19). Past mercies and deliverances are types and pledges of future.
§ 4. The contemplation of the Divine judgments produces in the people of God at first, fear and trembling at the prospect of chastisement