Brachos 7a: R. Yehoshua ben Levi intending to curse a certain heretic at the moment of Hashem's anger. At the moment, he fell asleep; he realized that Hashem did not want him to curse him - "v'Rachamav Al Kol Ma'asav," "Gam Anosh la'Tzadik Lo Tov."

Shabbos 149b: If someone is punished due to Ploni (Iyun Yakov - and Ploni desires this), Ploni does not enter Hashem's Mechitzah.

Rashi: Hashem did not say to wipe Yisrael's name from the land, for it was not good in His eyes to punish all of them.

R. Yonah: A Tzadik's Tefilah is heard - "u'Sfilas Tzadikim Yishma" (15:29). He can bless and punish. It is not good for him to punish one who sinned against him. It is proper for a Tzadik to pardon and overcome his Midos.

Malbim: Some things do not appear good and straight, e.g. that Hashem punishes a Tzadik. This begets the complaint 'a Tzadik suffers!' Refer to 17:27:1:3, 17:27:2:3.

Rashi: To strike the good among them, who were Nedivim of straightness ¹ - "v'Hish'arti v'Yisrael Shiv'as Alafim Kol ha'Birkayim Asher Lo Char'u la'Ba'al" (Melachim I, 19:18).

R. Yonah: Nedivim normally rule over the nation. They can strike and avenge one who sins against them. This is not good for Nedivim to do. Amidst generosity of their hearts, they bestow Chesed with their bodies and money. Amidst their Nedivus and Chesed, they should pardon those who sin against them.

Malbim: Hashem striking Nedivim appears Avel ba'Yosher (injustice). Refer to 17:27:1:3, 17:27:2:3.