Commentaire sur Les Nombres 20:16

וישמע קלנו HE HEARD OUR VOICE — through the blessing with which our father, Jacob, had blessed us — “the voice is Jacob’s voice” (Genesis 27:22), because whenever we cry we are answered (Midrash Tanchuma, Beshalach 9 on בשלח).

וישמע את קולנו, “He listened to our voice (prayer).” This was a reference to the power of prayer i.e. הקול קול יעקב, “the voice is the voice of Yaakov,” bequeathed by Yitzchak to his son Yaakov (Genesis 27,22).

Through the blessing … “The voice is the voice of Yaakov.” From the answer that the king of Edom gave to Moshe we see that Moshe said to him, “Through the blessing…” Meaning: The Torah writes shortly (v.18), “Lest I go out against you with the sword.” There Rashi explains the reason that he responded, “You pride yourselves…” This proves that Moshe [first] said to him, “Through the blessing…” (Devek Tov) For if not so, when Moshe said, “We cried out to Hashem…” he should merely have said, “Hashem heard and He sent…” Why did he mention “our voice”? Rather, it was “through the blessing…”