Why did the praise of Mo'av cease?
Malbim: Nevo, Kiryasayim and ha'Misgav were plundered. They were very praiseworthy.
What are "Cheshbon" and "Madmein"?
Rashi: They are places.
Why does it say "b'Cheshbon Chashvu"?
Radak: It is an eloquent expression [for the words are similar]. The same applies to "Madmein Tidomi" and "v'Ekron Te'aker" (Tzefanyah 2:4).
Malbim: The enemies counseled together to cut off Mo'av from being a nation.
What is the meaning of "Tidomi"?
Rashi: You will be destroyed.
What is the significance of "Madmein Tidomi"?
Radak: Refer to 48:2:3:1.
Malbim: Madmein was at the end of Mo'av's border. The refugees fled to there; also they will be destroyed - "Mei Dimon Mal'u Dam Ki Ashis Al Dimon Nosafos [li'Fleitas Mo'av]" (Yeshayah 15:9).