Why does it say "Ohr Zaru'a la'Tzadik7
Rashi (based on Shocher Tov): It is truly seeded; it is prepared to sprout for him.
Shemos Rabah (35:1): Hashem hid the light created on the first day. It is in Gan Eden, for Tzadikim, in the future.
Radak: In this world it is seeded for Tzadikim.
Malbim: Divine light is seeded in them. It is like a seed in their Nefesh prepared to increase, if they will water it and tend it like a planted seed. One who guards his Nefesh and does his Avodah, the seeded light will increase wondrously - "v'Orach Tzadikim k'Or Nogah" (Mishlei 4:18). The great prophetic light will come on him.
When will "Yishrei Lev" have Simchah?
Radak: They will harvest the light and Simchah in the future, in the days of Mashi'ach.
Malbim: It will be a spiritual Simchah, when Divine light shines in their Nefesh like a lamp on their heads - "Ohr Tzadikim Yismach" (Mishlei 13:9).
Mishnas R. Aharon 4 p.15: If the crookedness in one's heart is straightened, Simchah dwells on him.
