When will the humble eat?
Rashi: At the time of the redemption, in the days of Mashi'ach. Radak - the humble are Yisrael. The Nochrim were haughty, until the redemption of Yisrael.
Malbim: He discusses the Kohanim, who offer the Todah. The humble will eat the meat and be satiated, and afterwards they will praise Hashem.
Who are "Dorshav"?
Radak: They are Yisrael, who seek Hashem in Galus.
Who says "Yechi Levavchem Yachad"?
Rashi: All this I will say to them.
What is the meaning of "Yechi Levavchem Yachad"?
Radak: This is like "va'Techi Ru'ach Yakov" (Bereishis 45:27). It is the opposite of "va'Yamas Libo" (Shmuel I, 25:37). Ru'ach of the living is in the heart; when one is in affliction, his heart is dead - "Libi Chalal b'Kirbi" (109:22). When one leaves Tzarah and finds respite, his heart lives.
Malbim: It is as if the heart, which is nourished from the meat of the Korban, receives a spiritual influence from the Kodesh meat. Through it, it will live forever.
Why does it say "la'Ad"?
Radak: They will not be exiled again.