King, Amalek, Beit Hamikdash

There is a reference in the Parsha that deals with the three Mitzvot we are commanded to observe when we enter Eretz Yisrael. We are to appoint a king, destroy Amalek and build the Beit Hamikdash. The Gemara asks whether or not there is a specific order to these three Mitzvot. It is obvious that the appointment of a king should come first. But it is not clear what follows. Can the Temple be rebuilt without Amalek being destroyed? The answer to this question comes from the description of the future in the Parsha. First we are told that we must remove our enemies from the Land. Only then will we be able to build a dwelling place for the שכינה, Divine Presence. Amalek represents all that is evil and impure in the world. The Temple represents what is sacred and pure. The two extremes collide and the קדושה cannot tolerate such impurity. It must be erased before the Temple can be built.