It states (Tehillim 20:8-9) בסוסים ואלה ברכב אלה קמנו ואנחנו ונפלו כרעו המה ,נזכיר אלקינו 'ה בשם ואנחנו ונתעודד , "They come with chariots and horses, but we call out the name of Hashem, our G-d. They surrendered and fell, and we were triumphant and exultant."
The Radak explains that our enemies rely on their chariots and horses for victory (and in our times, tanks, planes, and missiles), but we rely on Hashem, and therefore, we will be victorious. They will surrender and fall before us. The Radak writes, "Initially, we had fallen before them, but when we invoke Hashem's name, we become triumphant, and we win the war."
The goyim have precision missiles, atomic bombs, etc., but we have tefillah, and we will be victorious. Tefillah is the most potent weapon. With tefillah, we will be victorious over all our enemies. Even if we have fallen and were defeated, קמנו, we will stand up again and be victorious.
People find it hard to imagine that words of tefillah can be so powerful. How can words compete with modern-day weaponry? But behold it states (Amos 4:13) הרים יוצר רוח ובורא שיחו ומה לאדם מגיד . The Rebbe of Ruzhin zt'l explained these words to mean, הרים יוצר, Hashem created mighty mountains, רוח ובורא, but wind can uproot mountains because winds are stronger than mountains. לאדם מגיד שיחו מה , this pasuk tells a person how powerful his speech is. Speech is ultimately only wind, yet wind is the greatest strength in the world.
It states (Yeshayah 41:14) ...יעקב תולעת תיראי את עזרתיך אני , "Fear not, O worm of Yaakov...for I help you." "Worm of Yaakov, יעקב תולעת, isn't said in a derogatory way. Rashi explains that the Jewish nation is compared to a worm because אלא גבורה לה שאין כתולעת החלשה בפיה , "[The Jewish nation] is weak like a worm, whose only strength is its mouth." The Midrash (Tanchuma Bishalach 9) states, "Why is Bnei Yisrael compared to a worm? A worm can attack cedar trees only with its mouth. The worm is soft, and it smites the hard (the tree). So too, Bnei Yisrael, their strength is their tefillos."
Sarah laughed when the malach said she would bear a child. The Siforno (18:12) explains, "She thought that a brachah from a navi [or malach] wasn't sufficient to cause an old couple to bear children and become young again. They would need a miracle similar to techiyas hameisim, and such a miracle would only happen if Hashem commanded it explicitly or through a tefillah that finds favor in Hashem's eyes."
So, we see that even if a brachah from a malach or a navi won't change one's nature, tefillah can. Tefillah brings us Hashem's miracles.
