1)
What is the subject of this Mizmor?
1.
Rashi: Refer to 11:1:2:1, 3.
2)
What is "Al Yedusun"?
1.
Rashi: It is about the Dasos (edicts) and Dinin (judgments) that come on Yisrael.
2.
Radak: It is like li'Ydusun. Also "va'Tispalel Al Hashem" (Shmuel I, 1:10) is like El Hashem.
3.
Radak citing a Midrash: It is about the change of Das (creed) in Galus. The Mizmor is about Galus.