What is the meaning of "va'Shem Chafetz Dake'o Hecheli"?
Rashi: Hashem wanted to crush him and make him repent, therefore He made him ill.
Radak: We see his pains and afflictions in Galus. This is only Hashem's desire. He persisted in His Torah, which is the true Torah, and handed himself over [to be killed] for it. We see no reason for his pains. Either he was punished for his sins, or Hashem wanted to crush him, and we do not know His desire.
Malbim: Because your fathers in prior generations under the hands of Nochrim were killed for Kedushas ha'Shem, Hashem wanted Lechalos (to assuage) and appease the crushing of that generation. He will benefit the last generation.
Why does it say "Im Tasim Asham Nafsho
Rashi: Hashem said, l will see if his Nefesh will be given and handed over in its Kedushah, to return to Me Asham for all that he transgressed. I will pay his recompense. 'Asham' is amends that one pays to the one against whom he sinned. This is like the Pelishtim said, "Al Teshalchu Oso Reikam Ki Hashev Tashivu Lo Asham" (Shmuel I, 6:3).
Radak: We see that he has a good reward for the evil that he suffered. If he put his Nefesh in a place of Asham [e.g. he put his grave] "Es Resha'im" (9), refer to 53:10:3:1.
Malbim: Hashem tells the enemy, even if you consider [Yisrael's] Nefesh to be liable, and sentenced him to death and executed him, Hashem wanted to appease his crushing of that generation. Even if you kill him, "his seed will succeed and live long."
Why does it say "Yir'eh Zera"?
Radak: He will have many children - "v'Ravu Kemo Ravu" (Zecharyah 10:8), "Arbeh Osam ka'Tzon Adam" (Yechezkel 36:37).
Do we find that he will live long?
Radak: Yes - "chi'Ymei ha'Etz Yemei Ami" (65:22), "v'Ish Mish'anto b'Yado me'Rov Yamim" (Zecharyah 8:4).
What is the meaning of "v'Chafetz Hashem b'Yado Yitzlach"?
Radak: In Galus, Hashem desired to crush him. As a reward for [suffering] this, he will prosper; Hashem will desire to increase him and benefit him greatly. Until now are the nations' words; after this, Hashem speaks.