How to Defeat Amalek
Chazal declared Parshas Zachor to be read on the Shabbos prior to Purim. Haman (a direct descendant of Amalek) and his followers were defeated during the miracle of Purim. This defeat was, in part, a fulfillment of the Divine command and promise to eliminate Amalek .
How does this sacred commandment apply to us today?
The Zohar Hakadosh  says that Satan is the heavenly officer of Amalek while other commentators say that Amalek refers to the Yetzer Hara (the evil inclination). In other words, when commanding us to obliterate the remembrance of Amalek, we are also commanded to blot out our own Yetzer Hara, which is our personal Amalek.
The Medrash  points out an acronym on the letters of Eisav’s name: Ha,-shav sheh’barasi beh-ohlomi – “Behold! There exists deceit which I created in my world .” This alludes to Eisav who used dishonesty to make Yitzchak think approvingly of him . Eisav is compared to the swine who smugly flaunts its split hooves (as if to say, “See, I am Kosher”), while actually remaining “non-Kosher” . Eisav married at the age of forty, just as his righteous father did – pretending to emulate him, but yet he engaged in sinful activities.
The Sheim MiShmuel  notes that lying and deception had already been introduced into the universe at the time of its inception. When the serpent spoke slanderously of Hashem to Chava (Eve) he stated that Hashem had eaten from the Tree of Knowldege and thus created the world. They too could be divine by doing the same !
The Sheim MiShmuel distinguishes between two distinct Hebrew words for falsehood – “sheker” and “shav”. “Sheker”, he proposes, refers to lying to others when the liar actually knows the truth. This was the case vis-à-vis the serpent.
“Shav” in the above mentioned Medrash refers to a lie where the liar fools himself, believing that he is being truthful, i.e., self-deception. From Eisav’s viewpoint, he was fully deserving of the birthright and blessings. Based on this self-deception, after Yitzchak warns Yaakov not to marry Canaanite women, Eisav married his uncle Yishmael’s daughter, but nonetheless, he did not divorce his previous two Canaanite wives! This was because he attributed his unworthiness of the blessings not to his sinful behavior but to his Canaanite children who were not fit to receive the blessing. In his erroneous belief he felt that this would be corrected by his fathering non-Canaanite children from Yishmael’s descendants. As such he saw no need to divorce his previous wives.
This attribute of deception and self-deception was further advanced by Eisav’s son Amalek. Our Rabbis  comment on how Amalek used deception to wage war against the Jews by dressing like Canaanites , using the pretense of wanting to trade with the Jewish people to approach them in order to attack them. The art of deception is pervasive and viral in nature. It implants within others both the ability to deceive and the capacity for self-deception, to obscure truth and clarity of vision.
The Navi says  שארית ישראל לא יעשו עולה ולא ידברו כזב ולא ימצא בפיה לשון תרמית – the remnant of Israel shall not do injustice nor speak lies; neither shall a deceitful tongue be found in their mouth. Reb Yehudah Hachasid  relates the following story in his Sefer Chasidim .
A sinner came to a wise man and said, “If you tell me how to do teshuva (repent) by doing one single act no matter how difficult, I will do it.” The wise man answered him, “Be extra careful never to tell a lie. Through this you will achieve complete penitence.” The wicked man said he would do it even though it would be very difficult.
At the next opportunity to steal he thought to himself, “If I get caught I will not be able to deny the theft I committed. I will be punished if I admit to the crime and I cannot lie to save myself.” Thus he refrained from stealing.
Similar thoughts repeated themselves in his mind for each sin he wanted to commit and kept him from carrying out any misdeeds. After a time he became a completely righteous man.
The Pasuk  tells us כי מחה אמחה את זכר עמלק – for I will utterly erase out the remembrance of Amalek (the words utterly ‘erase’ in the pasuk literally reads, “for erase, surely shall I erase the memory of Amalek”). Later the pasuk  says תמחה את זכר עמלק – Thou shall erase the remembrance of Amalek. In total the word “erase” (in one form or another in reference to the annihilation of Amalek) is repeated three times. “Moche” – erase, “Emcheh” surely shall I erase, and “Timche” – you shall erase. The first letters of these words that refer to the eradication of Amalek – “Emcheh”, “Moche”, “Timche” – spell out the Hebrew word ‘emet’ (emes) meaning truth. This can perhaps be what the Torah is alluding to with the acronym of ‘emes’, truth, when referring to the eradication of Amalek which is symbolic of our own personal evil inclination. The Torah is telling us that the key to defeating our own evil is to constantly be scrupulous in maintaining our own honesty and to be extra cautious that we do not deceive ourselves regarding our own righteousness.
Good Shabbos and a Happy Purim!