For the horse ... - This verse does not belong to the hymn, but marks the transition from it to the narrative.
Related Commentaries of Exodus 15:19
Exodus 15:19
19 For the horse of Pharaoh went in with his chariots and with his horsemen into the sea, and the LORD brought again the waters of the sea upon them; but the children of Israel went on dry land in the midst of the sea.