Midrash sa Deuteronomio 20:1: Mekhilta DeRabbi Yishmael, Tanna DeBei Eliyahu Rabbah, Midrash Tanchuma & Sifrei Devarim

(Exodus 15:1) "A horse and its rider He has cast into the sea": Now was there only one horse and one chariot? Is it not written (Ibid. 14:7) "And he took six hundred choice chariots"? — When Israel does the will of the L–rd, its foes oppose it, as it were, with one horse and its rider. Similarly, (Devarim 20:1) "When you go out to war against your enemy and you see horse and chariot." Now was there only one horse and one chariot? — When Israel does the will of the L–rd, etc."

Izevel, the daughter of Etba"al king of the Tzidonim and the wife of Achav, at the first time that she was brought before Achav taught him the ways of idol worshippers and because of her he was brought to become an idolater.

The horse and his rider (Exod. 15:1). Was there only one horse? (Of course not!) All the horses were considered by Him as one, as in the verse When thou goest forth to battle against thine enemy, and seest a horse and chariot (Deut. 20:1). All the horses were considered by Him as one in this instance as well. And his rider. Has it not already been stated that He took six hundred chariots (Exod. 14:7), and does not Scripture tell us Pharaoh’s chariots and his hosts (ibid. 15:4)? This indicates that when Israel performs the will of the Omnipotent One, all the nations are considered by Him as one horse and one chariot: The horse and his rider hath He thrown into the sea (ibid., v. 1). This verse informs us that the horse and the rider were joined together, and as Scripture tells us, they were cast (yarah) into the sea without separating. He hath thrown (ramah) into the sea and He Hath cast (yarah) into the sea imply that they were thrown into the depths of the sea. How can these two verses be reconciled? Thrown indicates that they were lifted up and then cast down. This indicates that they descended into the deep without separating.