In the 4th aliyah of Parshas Chukas, Moshe send messengers to the king of Edom, asking permission for Bnei Yisroel to pass through their land. This exchange begins with Moshe reminding Edom that we are brothers, and references the strength of Yaakov, which is in the voice of tefilah. Edom, a descendant of Esav, responds with reference to the sword of Esav, This happens right after Moshe hits the rock instead of speaking to it, which is as failure of the voice of Yaakov. We need to make sure to use our voice in tefilah, recognizing that what we have comes from Hashem, who responds to our voice. - Library: Bnai Jacob Shaarei Zion - RabbiHauer.org