"[The Rephaites] were a people strong and numerous, and as tall as the Anakites. The LORD destroyed them from before the Ammonites, who drove them out and settled in their place. The LORD had done the same for the descendants of Esau, who lived in Seir, when he destroyed the Horites from before them. They drove them out and have lived in their place to this day." -Deut.2:21-22
First of all, this little passage places a delicious and strong lie on the modern and post-modern devils who love to speak of biblical theologies of conquest as "nationalistic self-legitimations" and " national stories which justify colonial oppression." Pathetic. Both the Ammonites and the Edomites were mortal enemies of Israel, as is amply testified by biblical literature and archaeological findings. If biblical theologies of conquest had anything to do with nationalism and self-legitimation, they would not go out of their way to speak of the LORD (Israel's so-called patron deity!!) assisting and helping ENEMIES in their territorial warfare. Nationalism falls to the ground as an appropriate model for understanding what is at work here.
Furthermore, this scripture tells us that you do not have to be a nation at peace with YHWH for Him to do battle for you. The modern Christian scholar, who wishes to have it known that he is a jew-everything and will adopt meaningless Jewish phrases like "Torah" (as if Rabbinic terminology is somehow appropriate and non-anachronistic for dealing with literature written centuries before there was such a thing as a sodding Rabbi) has yet to be "instructed" on this count. Deuteronomy is the eternal Word of God, given by the lips of Jesus the eternal Lord. We find in it boundless instruction. And in this particular word of God, we learn that it is the Way of YHWH to assist godless nations in conquest. He does this for His own purposes and ends. As such we cannot absolutely condemn conquest today when it occurs, for who are we- mere men- to determine whether the hand of our God might not be behind it?