BEIS The concept here is that the war that the B’nei Yisroel have to wage (רִיבָּם their battle) refers to the general battle with [the forces of the other side] - the Le’umas Zeh: The other side, The Sitra Achra, the side opposite to holiness. There is a Possuk in Koheles (7:14) that states: זֶּה לְעֻמַת־זֶּה עָשָה הָאֱלֹקִּים “Hashem has made this one opposite that one”. In Chassidus it explains that HaShem created the world with a fine balance of good and evil in order to give us a perfect choice of two equal paths. And therefore, what He gave to one He gave to the other.
That they: The B’nei Yisroel. Dwelling for HaShem blessed be He: As the words of our sages of blessed memory, that HaKodosh Boruch Hu 'Desired' to have a dwelling in the lower worlds, specifically that the lowest of the worlds shall be a receptacle suitable for the Divine presence to rest and to be revealed within them. It is explained in Chassidus, that this is the ultimate purpose, the raison d'etre for the creation of the world.
As in the parable of the preparations of a suitable dwelling for an important person coming to stay, and how much more so for a King, and especially how much more so if preparing a dwelling for a great, awesome King, that the property would first have to be cleared of any undesirables, and only then can beautiful furniture and ornaments be brought in, until it shall be suitable as a dwelling for ‘The King’.
