Where will he have length of days?
Radak #1: In this world. Malbim - we find that Iyov received length of days due to his afflictions.
Radak #2: In the world to come.
What is the meaning of "v'Ar'ehu bi'Yshu'asi"?
Shocher Tov (8): This is a difficult verse. It says that the salvation of Hashem 1 is the salvation of Yisrael.
Radak #1: In the world to come, his Nefesh will be saved in front of Me.
Radak #2: If this Chasid will die in Galus, when I will save Yisrael from Galus in the days of Mashi'ach, I will revive him from the dead [to see the salvation].
Malbim: I will show to him salvation via Hashgachah.
I.e. it is as if Hashem needed salvation; refer to 91:15:21:2]. Brachos 7a similarly learns from "b'Veis Tefilasi" (Yeshayah 56:7) that Hashem prays. However, according to Radak (refer to 2:6:2:1), Yeshu'asi can mean the salvation that I did! (PF)