The Shabbat prior to the feast of Purim is known as the “Shabbat of Remembrance” (Shabbat “Zachor”) because in the book of Esther is the command to “remember the Amalekites” and what they did to Israel during their forty years of wandering in the wilderness: “17 Remember what the Amalekites did to you as you were coming out of Egypt? 18 They found you on the road when you were all worn out, and they attacked those who had fallen behind and were isolated and defenseless. They showed no fear of God. 19 When you’re in a position to punish them for this, when all of your other enemies are defeated and you’re living peacefully in the land that the Eternal your God is giving you to live in, then wipe out every trace of the Amalekites under the sky. Don’t forget!” Deut. 25:17-19

The question we must ask is why remember the deeds of this specific enemy rather than forgive as commanded (i.e., “Love your neighbour as yourself”; “43 You have been taught to love your neighbour and hate your enemy.[a] 44 But I tell you this: love your enemies. Pray for those who torment you and persecute you— 45 in so doing, you become children of your Father in heaven. He, after all, loves each of us—good and evil, kind and cruel. He causes the sun to rise and shine on evil and good alike. He causes the rain to water the fields of the righteous and the fields of the sinner. 46 It is easy to love those who love you—even a tax collector can love those who love him. 47 And it is easy to greet your friends—even outsiders do that! 48 But you are called to something higher: “Be perfect, as your Father in heaven is perfect.” – Matt. 5:45-48

In rabbinic literature, the commands against the Amalekites were that:

Amalek is the enemy who will never reconcile and it is forbidden to show mercy foolishly to one wholly dedicated to the destruction of Israel (cf., Prov. 12). Rather than sit back and encourage evil, we fight against it with every part of our being. Rather than be a spectator of evil, we demonstrate our love to its victims which is the greater love. A midrash teaches that all the tragedies which Israel suffered are considered the direct outcome of Amalek’s hostile act (Agadah -PdRK 27). Behind all the hostilities throughout the ages against the Jewish people lies the demonic spirit of anti-Semitism. This is why on Holocaust Day we say: “We will never forget!”
(2) The command to “remember” is not to recall the evil actions of others but rather our own. Our greatest enemy is sin and to this we will never be reconciled.
(3) The command to “remember…” is for all generations, to know that what we sow we will reap.

Raphael ben Levi