What is the grammatical form of "u'Maher"?
Radak: It means quickly. It is an adjective, with the form of "v'Shabe'ach Ani Es ha'Mesim" (Koheles 4:2).
Why does it say "Karov" and "Maher"?
Malbim: It is close in time, and it is hastening its coming via causes.
What is the meaning of "Mar Tzore'ach Sham Gibor"?
Rashi: The Gibor will scream there in a bitter voice.
Radak: Tzore'ach is raising the voice. Similarly, "va'Yavo'u El Tzeri'ach" (Shoftim 9:46) is a high place. It is as if Yom Hashem calls and raises its voice. Sham Gibor - Giborim will come there to kill them, or there Giborim will be killed. Yonason translates like the latter.
Malbim: The verse depicts that a Gibor screams there in a bitter voice "Yom Hashem!" I.e. it is coming.
