Who will be to Hashem?
Radak: Yir'ei Hashem of this generation who will be in Techiyas ha'Mesim, and Yir'ei Hashem of that generation.
What does Hashem make a Segulah?
Rashi: I stored a day away to pay My recompense. There I will show to you the difference between Tzadik and Rasha!
Radak: It is a day of judgment of Resha'im. [Yir'ei Hashem] will be a Segulah to Me, and I will have mercy on them. The evil that eradicates the Resha'im will not touch them.
Malbim: Hashem makes them a stored treasure for that day. Just like they served amidst love, they will be a Segulah for Hashem, and they will receive a Segulah and desired storehouse.
What do we learn from "ha'Oved Oso"?
Radak: A father has mercy on all his children - "k'Rachem Av Al Banim" (Tehilim 103:13), but even more on one who serves him.
Malbim: One who works for wages, he is paid immediately. A son who serves his father amidst love, his father does not pay him immediately. He stores for him a Segulah that will last for generations and not be lost. So those who serve amidst love, and not amidst hope for reward, He does not pay them in this fleeting world, for then the reward would pass. Rather, He stores their reward for the future, in the eternal world, so the reward will be great, eternal and unlimited.
