Exodus 15:19

For the horse of Pharaoh went in with his chariots and with
his horsemen into the sea
Meaning not that particular and single horse on which Pharaoh was carried, but all the horses of his that drew in his chariots, and all on which his cavalry was mounted; these all went into the Red sea, following the Israelites thither: these words are either the concluding part of the song, recapitulating and reducing into a compendium the subject matter of it; or are a reason why Moses and the children of Israel sung it; or else they are to be connected more strictly with the preceding verse, and give a reason why the Lord reigns over his people for ever; because he has destroyed their enemies, and delivered them out of their hands: and the Lord brought again the waters of the sea upon them;
after he had divided them, for the Israelites to pass through them, he caused them to close again, and to fall upon the Egyptians and cover and drown them: but the children of Israel went on dry land in the midst of the sea;
which was a very wonderful thing, and was a just and sufficient reason for singing the above song to the Lord, see ( Exodus 14:29 ) .