He stirred the sea (compare Exodus 14:21; Mark 4:39; compare Isaiah 51:15; Jeremiah 31:35). God performed a miracle for his people.
He shattered Rahab: God showed control over the sea symbolized as a monster ("Rahab"), challenging myths about the sea being divine. See also Psalms 74:13–14; 89:9–10; Isaiah 27:1; 51:9–10.