Defeating the Amalek Within Us All
"Remember what Amalek did to you when you were tired and worn out and did not fear G-d." (Devarim 25:17-18)
Not only are Bnei Yisroel the seed of Yaakov commanded to wipe out Amalek, the seed of Esav, but each and every Jew must wipe out the evil portion within himself hidden within his own heart which is known as his own personal Amalek. For so long as the seed of Amalek remains in the world then since man is a microcosm of the world and he is called an Olam Katan - a small miniature world within himself then there exists within his own world an Amalek, a power of evil as well. And this mini Amalek awakens time and time again to push man to sin, and this is why the Torah reminds us about him.
The power of Bnei Yisroel and the seed of Yaakov is in their mouths, [as in the verse] "the voice is the voice of Yaakov," this emerges through Torah study and prayer. And when a person has this power and his heart is continuously aflame to serve Hashem then no evil can control him. However if he does not utilize this power [and is reticent in Torah study and prayer] then immediately "they traveled from Refidim,' [as Rashi explains] Rafu Yadeyhim min haTorah – their weakened their hand's grasp on the study of Torah. And then immediately it follows that "Amalek came," the evil immediately takes hold of him. However when a person at least grasps hold of the attribute of fear, to fear Hashem, and to fear any transgression of His commandments then he at least saves himself from sin.
This is why the verse says that "you were tired and worn out," it alludes to the lack of the power of the seed of Israel, since they weakened their grasp from serving Hashem. And "they did not fear G-d," [and this they lacked as well].
You should always remind yourself of this so that Amalek should not be able to cause you to stumble. This is why the verse says "Mecho Emche – I will erase and blot out Amalek," erase and wipe the root of evil [symbolized by Amalek] out of your heart and subdue and subjugate him to do good. This is as it says (Shemos 17:11) And it was as Moshe raised his hand that Yisroel were winning and when he lowered his hands then Amalek were winning," this refers to his power which is called his hand, when you uplift and strengthen your power then Bnei Yisroel emerge victorious. However if you put your hands down, and heaven forbid you do not utilize this power [of the mouth through Torah study and prayer] then [Amalek can win].