Rashi: Is this the city that was happy in your eyes? It fell!

Malbim: The verse asks people of the world - did you ever hear that a happy city will abandon its place to go to a far place?! Who counseled Tzor to do so - Elokim! (a) It is normal for people to leave a bad place that does not make its residents happy - Tzor was happy! (b) If they dwelled there a short time, it is easy to leave - they were there from days of old!

Radak: This is a noun, like "she'Kadmas Shalaf Yavesh" (Tehilim 129:6). The Mapik (Dagesh, i.e. dot in the) Hei at the end is feminine (its beginning).

Radak: Bal Korcho (against its will) it will go to exile on foot to a far land. This is like it says, a man's feet are guarantors for him, to bring him to the place where he needs to be (Sukah 53a).

Malbim: (a) Normally, people leave a place only if they know to where they will go - Tzor will go to where their feet bring them - they do not know where! (b) Sometimes people leave to go nearby, even if they do not know exactly where, for they know the essence of the country - Tzor will go far! (c) Sometimes one will go far to look for a place - but he will not bring his household and Kelim. Tzor went Lagur - they already uprooted from their initial place.