Radak, Malbim #1: It is about Bnei Galus, as if each prays the Tefilah of this Mizmor.
2.
Malbim #2: It discusses the entire nation as an individual.
2)
Why does it say "le'Ani"?
1.
Rashi: This refers to Yisrael - a poor nation.
2.
Michtav me'Eliyahu (5, p.428): This is one poor in Da'as. Even though he has complaints against Hashem in his Tefilah, Hashem esteems his Tefilah greatly, just like the Tefilah of one who is far [from Hashem] completes the Tefilah of the Tzibur.
1
Kerisus 6b: Any fast that does not include (penitent) sinners is not a proper fast. We learn from Chelbenah. It smells bad, yet it is included with the spices for the Ketores.
3)
What is the meaning of "Ki Ya'atof"?
1.
Rashi: His Nefesh is wrapped in affliction.
2.
Radak: One who prays amidst great affliction, he bends himself, as if one end [of him] is wrapped in the other end.
3.
Malbim: His Nefesh is weak amidst afflictions; it faints, and it is about to leave his body. Before it leaves, it pours its words in front of Hashem, and prays about the Galus and the salvation.
