When will this Nevu'ah be fulfilled?
Radak: It will be in the future 1 , like Yeshayah's Nevu'ah about Edom. Also Ovadyah, Yechezkel and all [who prophesized about Edom], the Nevu'os imply that they are for the future. And so it says "Im Lo Yischavum Tze'irei ha'Tzon" (verse 20), i.e. Yisrael.
Malbim: Edom was destroyed several times, like Yeshayah prophesized (Perek 34). This Nevu'ah includes two destructions - nowadays and in the future. I explained in Yeshayah (21:11) that when (i.e. the way that) Edom was destroyed, its neighbors enticed it to go outside its border. It seems that it went to fight Bnei Dedan 2 . Bnei Dedan distanced, and Edom chased them. When they were far from their border, the enemy came and destroyed Edom.
I.e. it has not yet been fulfilled. Presumably, it will be around the time of Mashi'ach. (PF)
Dedan was Avraham's grandson, from Keturah (Bereishis 25:1-3).
Why does it mention Chachmah?
Radak: Also in Ovadyah (1:8), it says "v'Ha'avadti Chachamim me'Edom." Chachmah is found among Edom. At the time of their calamity, it does not help them.
Malbim: It was foolish for them to distance from their border and not guard their land from the enemy! (Refer to 49:7:1:2.)
Why does it say "b'Seiman"?
Rashi: Edom is south of Eretz Yisrael, like it says "v'Hayah Lachem Pe'as Negev
I.e. the place where he settled was called Teiman, after him.
What is the meaning of "mi'Banim"?
Rashi: From this generation 1 [in which this punishment will come]. Radak - this is like Targum Yonasan, 'from sons.'
Radak: It is an expression of Tevunah (understanding), like "Bantah l'Re'i" (Tehilim 139:2). Also in Ovadyah (1:8) it says "u'Sevunah me'Har Esav."
Malbim: Until now, there were clever people among them.
What is the meaning of "Nisrachah"?
Rashi: Was spoiled. Radak - this is like 'Tipah Seruchah' (Avos 3:1).