Radak citing Sanhedrin 98a: Mashi'ach can come in a totally unworthy generation- "va'Yar Ki Ein Ish", "Lema'ani E'eseh" (48:11). Also refer to 60:21:1:1.

Rashi: Now that Hashem regrets the evil to His nation, he sees that there is no one to stand in (mend) the breach.

Radak: There is a contradiction in verses. Some imply that that the gathering of exiles will be via Teshuvah ¹ . Other verses imply that it will be without Teshuvah ² . Chachamim argued about this ³ . We can resolve - most Yisraelim will repent after they see signs of Ge'ulah. It says va'Yar Ki Ein Ish, for they repent only after seeing signs of Ge'ulah. There are still sinners and rebels among them. Most of Yisrael, who repent, will leave Galus; they will die on the road and not come to Eretz Yisrael ⁴ . "Ein Ish" - most will not do full Teshuvah. "Ish" refers to Klal Yisrael - "v'Ish Yisrael Nishba ba'Mitzpah" (Shoftim 21:1). All of Yisrael were there. It cannot be that there will not be Tzadikim in Yisrael worthy of Ge'ulah - but their merit is not enough to redeem all of Yisrael. 'A totally unworthy generation' (refer to 59:16:1:1) refers to the majority; there was never a generation without Tzadikim. Also those liable do not deserve eradication, just they are not worthy of Ge'ulah.

Malbim: After telling the lowliness of Yisrael and their evil deeds, it seems that when Hashem sees this, He will do for the sake of His great name and redeem them with His Chesed, even though they are not worthy. Salvation in the merit of Yisrael is via two ways. (a) Via the merit of the Klal, based on their deeds. This is called Ozer (63:5). It helps to save. (b) Via a Tzadik's Tefilah and request; this is called Somech (ibid.); it is not a full help. "Ein Ish" - who will help via the merit of his deeds

Rashi: He was quiet, to see if there is Mafgi'a. He saw that there is not, va'Yishtomem - like a man who stands, is astounded and is silent in his astonishment. The root is Shamem. When the first letter of the root is Shin or Samech, in Hispa'el conjugation; the Tov is added after the first letter of the root. The same applies to Mishtolel (15). Yishtomem is like "Shomo Shamayim" (Yirmeyah 2:12), "Mashmim b'Socham" (Yechezkel 3:15), "Nashamu Acharonim" (Iyov 18:20) [Radak - and "Eshtomem k'Sha'ah Chada" (Daniel 4:16) - expressions of bewilderment.

Malbim: Not only was there no one with merit to help bring salvation - there was not even a Tzadik praying for the Klal! This was astounding.

Radak: They will not pray with a proper heart until they see signs of Ge'ulah. Mafgi'a is Tefilah, like "v'Al Tifga Bi" (Yirmeyah 7:16).

Malbim: Refer to 59:16:2:2.

Rashi: He will take vengeance from His enemies.

Radak: There is no one to help and support His nation, only His strength and virtue. Man's deeds and virtue are like helpers to save him. Zero'o refer to taking vengeance against the Nochrim - "ha'Yukach mi'Gibor Malko'ach" (49:24). It says va'Tosha Lo - for Himself, for it is incumbent on a master to save his servant from those who hold him and make him work for them, like the Nochrim did to us. Via salvation of the slave, the master is 'saved', i.e. his name is aggrandized.

Malbim: Zero'a refers to what Hashem does by Himself, without 'help' from people's merits; it moves the lower arm. Here, there was no Ish whose merits would help.

Rashi: This will entice and invigorate Him to take His vengeance, even though we are not worthy to be saved.

Radak: Tzidkaso corresponds to the Avos; He remembered His Bris with them and their seed after them, and does Tzedakah with them to take them out of Galus.

Malbim: There was no support from Tefilah of Tzadikim; it was purely supreme Tzedakah.