Radak: It discusses Galus, man's weakness and brevity of days. He prays that Hashem not punish him according to his deeds, like Iyov said "ha'Lo Me'at Yamai va'Chadal" (10:20).

Malbim: This and the next Mizmor are Tefilos about the brevity of man's days, and that his days are full of folly, and he cannot attain the purpose for which he was created. The answer to the Tefilah is in the next Mizmor - one who dwells in Hashem's shade, he is guarded from bad occurrences. He will live long, and complete in his lifetime what he should complete. The reason for the brevity of man's days, and bad occurrences, is because he did not take refuge in Hashem's shade! Therefore, he is left to chance and evil occurrences of time.

Rashi (from Shocher Tov): Yes. In fact, he composed the coming 11 Mizmorim, until "l'David Mizmor" (101:1). (Radak 91:1 - all those in between do not name the author; they are Samuch to "Tefilah l'Moshe.") Correspondingly, he gave 11 Brachos to 11 Shevatim ¹ in v'Zos ha'Brachah.

Radak: Yes. David found it written, and he had a tradition that it was from Moshe, and wrote it in his Sefer.

Radak citing Rav Sadya Gaon: No. "L'Moshe" is like li'Vnei Moshei; Moshe's descendants were Leviyim, who sang in the Mikdash. This is like "li'Vnei Korach Mizmor" (47:1). We find like this, that 'Bnei' is omitted - "v'Yehoyada ha'Nagid l'Aharon" - it means, li'Vnei Aharon.

Radak, Targum Onkelos (Devarim 33:1): He was a Navi.

Rashi: It is a residence and a place to escape.

Radak: It is a place and a refuge for Yisrael in all generations. Also "Me'onah Elokei Kedem" (Devarim 33:27) means that He is the place of the world ¹ .

Rashi: From always, for You were before everything.

Malbim: This informs a great matter. All the Ruchos and Neshamos that will be created, they already had an existence from the beginning, in their exalted source - in Hashem Elokei ha'Ruchos. The only difference between before man comes into existence and after is that after, he has a physical garment subject to time, place and natural laws. These are not his essential existence. His essence - his spiritual Nefesh - does not change. It only moves, like a drop of water that leaves its source. Also after death, there is no essential change, only change of place. It rises from the lower world, in which it dwelled among physical beings and was impressed with them, to a spiritual place, its source, where it was initially. In all generations before man was formed, Hashem was his residence. This is not only after the creation of Shamayim and Aretz, rather, even before.