The Egyptians saw that Pharaoh had entered the sea, and all of them entered the sea after him, as it is said, "And the Egyptians pursued after them" (Ex. 14:23). Forth-with the waters returned, and covered them, as it is said, "And the waters returned, and covered || the chariots, and the horsemen" (Ex. 14:28).
Ben 'Azzai said: Everything is (judged according to the principle of) measure (for measure); just as the Egyptians were proud, and cast the male children into the river, so the Holy One, blessed be He, cast them into the sea, as it is said, "I will sing unto the Lord, for he hath triumphed triumphantly; the horse and his rider hath he thrown into the sea" (Ex. 15:1).