Why does it say "Lema'an Tziyon"?
Rashi: Due to what they did to Tziyon.
Radak: My name is called on it.
Malbim: Tziyon represents the virtue of Yisrael. The Sanhedrin and Mikdash were there. Yerushalayim refers to the salvation of Yisrael. Most of the people dwelled there, and the scattered of Yisrael gather to there. "Livshi Uzech Tziyon Livshi Bigdei Yeshu'asech Yerushalayim" (52:1). Tziyon wears inner strength - spiritual success. Yerushalayim wears outer garments - physical success. To clarify the virtue of Yisrael and the Emes of their Torah, one must debate with words and claims. I will not be quiet from doing so.
Why does it add "Lo Eshkot"?
Rashi: There will not be Shalom in front of Me "Ad Yetzei cha'Nogah Tzedakah."
Radak: The matter is repeated in different words. Also Yerushalayim is the same as Tziyon, just the fortress is called Tziyon.
Malbim: Refer to 62:1:1:3. To save Yisrael from Galus, action is needed - I will not rest. Rather, I will be zealous to save them.
What is "cha'Nogah Tzidkah"?
Malbim: Tzidkah is the virtue of Yisrael's Torah and Emunah. Nogah is something that does not have its own light; it receives its light from something else, like the moon receives from the sun. It is as if the "Lapid" (torch) will illuminate the night with the light of salvation, and via this their Tzedakah will be recognized.
What is the comparison to a burning torch?
Radak: People see it from afar. So your virtue and salvation, the distant Goyim will see it.
Malbim: Refer to 62:1:3:1.
