On the Shabbat before the festival of Purim, in the Torah reading, a paragraph is added that contains two of the Mitzvot of the Torah: that of remembering the evil of Amalek and that of eradicating it from the face of the earth.
The connection to Purim is simple, since Haman, the evil minister of the Persian empire who tried to destroy the Jewish people, was a descendant of Amalek.
Today we do not know who is descended from Amalek, which might give the impression that the mitzvah of eliminating Amalek no longer applies. However, God's will (i.e., the mitzvot) is eternal and unchanging, so this mitzvah still exists today.
When one analyzes and studies the Hebrew language, one quickly sees that it is a divine language. Unlike other languages that are merely a common agreement among people on how to name certain objects and/or situations, Hebrew is a language created by God.
Each letter corresponds to a number, and different words that add up to the same number (when the letters that compose them are added together) have a relationship with each other. This is called Gematria. The word Amalek adds up to 240. The word Safek (doubt) adds up to 240.
From this we learn the practical application of the Mitzvah of eliminating Amalek: Amalek is the force within each person that generates doubts about the existence of God, the truthfulness of the Written and Oral Torah, faith in the Sages, etc.
Just as Amalek attacked the Jewish people before they first entered the Land of Israel, so too does he attack the Jewish people before they enter the Land of Israel with the final Redemption and the coming of the Messiah. We must prepare ourselves through study, open-mindedness, mutual respect, and love for our neighbor to eradicate doubt and receive the Messiah NOW!.