"from the first-born of Pharaoh sitting on his throne": Scripture hereby apprises us that Pharaoh (himself) was a first-born, (the throne passing in succession to the first-born). But perhaps the intent is only to teach that his son was a first-born?—"sitting on his throne" already speaks of his son. Why (the redundant) "from the first-born of Pharaoh"? To apprise us that Pharaoh himself was a first-born. He alone remained (alive) of all the first-born. Of this, Scripture states (Ibid. 9:16) :But because of this I have preserved you, in order to show you My might, etc." (Likewise,) Ba'al Tzefon remained (standing) of all the Egyptian idols in order to raise their hopes. Of such as these it is written (Iyyov 12:23) "He lifts up nations and destroys them."