Listen to the contemporary music of Timche et zecher Amoleik and read about this Shabbat and its significance nowadays.
The reading for Shabbat Zakhor is very troubling for many Jews: a passage commanding us to remember (zakhor) the treachery of Amalek and to blot out their memory. (Deuteronomy 25:17-19). The Amalekites were a tribe of people who came upon the Israelites shortly after their flight from Egypt and attacked them from behind, preying upon the weakest of an exhausted group of people. See Exodus 17:8-16 and Deuteronomy 25:17-19.
Many find this commandment troubling because, in ordering us to "blot out the remembrance of Amalek," it appears to advocate genocide, killing people because of their race. Shabbat Zakhor's corresponding haftarah portion (I Samuel 15) is even more explicit on this point, ordering Saul to kill the men, women, children and cattle of Amalek.
The sages have long understood the commandment in Parshat Zakhor as a command to blot out the type of people that Amalek represents: those that prey upon the weak, those who do not believe in justice, those who hate without reason. The sages use the term "Amalek" as a shorthand for vicious, evil people who behave like mad dogs, in much the same way that many people today casually toss around the term "Nazi" to refer to anyone they disagree with rather than to Germans or members of the National Socialist party. It is these evil people that we are commanded to destroy, the sages say, not any specific ethnic group. This understanding of the term is quite clear in 15th century Sephardic commentary Me'am Loez, which said, "In every generation Amalek rises to destroy us, and each time he clothes himself in a different nation."
In addition, many scholars have suggested that the best way to "blot out" these evil people is to turn them away from their evil. If an Amalekite were to accept basic principles of morality (see The Seven Laws of Noah), the sages say, he would cease to be an Amalekite and would not be someone whose memory we are commanded to blot out. Likewise, someone who chooses to behave in this way becomes an Amalekite whether he is born to that nation or not, as Me'am Loez said.
For further discussion of whether Amalek is a racial designation and this is a commandment to genocide, see A Question of Race on Aish.com.
Shabbat Zakhor occurs on the Shabbat before Purim, because Haman, the villain of the Purim story, was an Amalekite. The Book of Esther describes Haman as an "Agagite," that is, a descendant of Agag, King of the Amalekites, who was spared by Saul contrary to Divine commandment in the haftarah portion.