What does Deuteronomy 2:18 mean?

Moreover Yahweh’s hand was against them, to destroy them from the middle of the camp, until they were consumed.

So, when all the men of war were consumed and dead from among the people,

Yahweh spoke to me, saying,

When you come near the border of the children of Ammon, don’t bother them, nor contend with them; for I will not give you any of the land of the children of Ammon for a possession; because I have given it to the children of Lot for a possession.”

(That also is considered a land of Rephaim: Rephaim lived there before; but the Ammonites call them Zamzummim,

a great people, many, and tall, as the Anakim; but Yahweh destroyed them before them; and they succeeded them, and lived in their place;