Rashbam: This Pasuk is a continuation of the father's answer to his son, the Tam. ¹

Seforno: It is a second answer to his question, inasmuch as Pharaoh (who is compared to a donkey), ¹ could have redeemed himself by sending out Yisrael (who are compared to a lamb). ² And because he refused, Hashem (Yisrael's Master), broke his neck (i.e. killed his firstborn).

Oznayim la'Torah: Refer to 13:13:2.3:2.

Seforno: Because, in reality, the firstborn of Yisrael, who were unworthy of miracles, ought to have died together with their Egyptian counterparts. ¹ And in order to rescue them, Hashem declared them holy - like Nezirim or perhaps even more so ² - requiring them to be redeemed.