1)
Will people who speak Sheker perish?
1.
Radak: You will make them cease from in front of You. The verse ends in the third person; verses often switch between second and third person.
2.
Malbim: No one will justify him in front of You, for Hashem despises a man of violence and deception. I.e. the nature of the Divine despises him. Nations think that the gods like him - this is folly and contrary to the Divine.
2)
Who is "Ish Damim u'Mirmah"?
1.
Rashi: It is Amalek and his seed.
