Another wonder occurred. When David threw the five stones and killed Goliath, instead of falling backward as the slain usually do, he fell forward. By what merit? By the merit of using לֹהֵ ינוּ ה' אֶ חָ ד-שְׁמַע יִשְׂרָאֵל ה' אֱ together with Yaakov Avinu’s staff, which revealed to us the power to overcome Eisav! The Yalkut Reuveni says, when Yaakov stood before Eisav, he recited Shema! The Midrash Talpiot adds, Yaakov said before Hakadosh Baruch Hu, "Even if I have no merit but the recitation of Shema alone, I am worthy that You save me from Eisav."
Haman knew the power of שׁ ְ מ ַ ע י ִ ש ׂ ְ רָ א ֵ ל, and therefore wanted to hang Mordechai before the time came to recite Shema. Mordechai knew the power of שׁ ְ מ ַ ע י ִ ש ׂ ְ רָ א ֵ ל, and therefore, when he was on the horse, he recited Shema! The Gemara says (Sotah 42a): Hakadosh Baruch Hu said to Yisrael, "Even if you have not fulfilled any Mitzvah except reciting Shema of the morning and the evening, you will not be delivered into the hands of your enemies." The Ben Yehoyada adds (Sotah) that the 25 letters of שׁ ְ מ ַ ע י ִ ש ׂ ְ רָ א ֵ ל are a double-edged sword to cut down Israel’s enemies: רוֹמְמוֹת אֵל בִּגְרוֹנָם וְחֶרֶב פִּיפִי וֹת בְּיָדָם – The high praises of G-d are in their mouth, and a two-edged sword in their hand. Goliath sensed this fate and wanted to prevent them from reciting Shema morning and evening. Thus, regarding Moshe Rabbeinu, in killing the Egyptian, it is written: וַי יִפֶן כֹּה וָכֹה וַיַהֲרֹג אֶת הַמִּצְרִי – And he turned this way and that way, and he killed the Egyptian. He recalled the unity of twenty-five and twenty-five of the morning and evening.
With this, we can explain what Yosef sent to Yaakov Avinu to tell him: כּ ֹה אָמַ ר בִּנְך יוסֵף שָׂמַ נִי אֱלֹהִים לְאָדוֹן לְפַרְ עֹה – Thus says your son Yosef, G-d has made me lord over Pharaoh. Meaning, through the twenty-five letters – כּ ֹה – of "your son Yosef," Hakadosh Baruch Hu made him viceroy. Yosef drew this sword against the klipot of Egypt and Pharaoh and prevailed over them. Thus, it says here, "Even if you only fulfilled Shema morning and evening, you will not be delivered into their hands," for these will be a double-edged sword against your enemies.
