Who is "Ish Lashon"?
Rashi: It is Esav, "Ki Tzayid b'Fiv" - he trapped (deceived) his father with his mouth.
Radak: It is Do'eg, who was a Ba'al Leshon [ha'Ra].
Malbim: It is a Ba'al Leshon ha'Ra.
What is the meaning of "Bal Yikon ba'Aretz"?
Radak: He will not be proper and elevated in the land. Rather, he will come to lowliness.
Malbim: He cannot last in the land. He will flee to mountain tops, and from there he will be trapped.
What should trap what?
Rashi: The evil that he does should trap him. Malbim - their evil is personified, and called "Ish Chamas." It will trap him from any mountain or hill on which he will be found, and push him to deep pits full of fire.
What is "l'Madchefos"?
Radak: He should be pushed from evil to evil.
