Why does it say "Nusu Maletu Nafshechem v'Sihyenah"?
Radak: Your souls will be in the place to which you escape.
Malbim: This is a command. [Since it was prophesized that Mo'av will be defeated,] do not fight. Save your souls via fleeing!
What is "k'Aro'er"?
Rashi, based on Targum Yonasan: It is the tower of Aro'er in the Midbar. There is no settlement around it, only tent-dwellers. A tower without settlement looks like a ruin.
Rashi citing Menachem: It is a kind of tree of the forest.
Radak: It is a tree that grows in the Midbar, in dry land 1 . After you leave your cities and flee, your cities will be like Aro'er in the Midbar.
Malbim: It is the name of a city of Mo'av 2 that was in the Midbar, separated from settlement. So you will dwell in the Midbar!
Perhaps it is cactus. (PF)
We find that Sichon ruled in Aro'er (Yehoshua 12:2), and he took Mo'av's land (Bamidbar 21:26). (PF)
