Why does it say "Mah Yisron ha'Oseh"?
Rav Sadya Gaon: If so 1 , there is no benefit to all that one toils in it.
Rashi: What is the advantage of one who does evil, in all that he toils? In the end, his time will come, and all will be lost.
Rashbam: This refers to "ul'Chotei Nasan Inyan Le'esof" (2:26). Since there are times for good and times for evil, also this sinner - when he gathers the money, and when it leaves him, to give it to someone good [in front of Hashem], what benefit did he have from his toil? It left him! "Oseh" is gathers, like "Asah Li Es ha'Chayil ha'Zeh" (Devarim 8:17).
Ri Kara: This refers to matters that are Simchah at the beginning, and sadness at the end. Since everything will be finished off, and everyone is destined to die, I am astounded - why are they happy when they toil in these matters? They know that in the end they will be Batel!
Rid: Even if man would live forever, since times change, sometimes one builds a house, and the time changes, and tomorrow it is destroyed! And even if times would not change, since man dies, he has no gain from his toil!
R. Avigdor: The Gematriya of these words equals that of Lo l'Shem Shamayim. (There is no gain in such matters.)
Seforno: This arouses a Safek about the Creator. He intends that man reach human perfection. How did He obligate him to toil and strive to attain his needs for temporary life?!
Metzudas David: Since it is man's nature that sometimes he wants this matter, and sometimes its opposite, what gain is there from doing his toil to get his desire? There is a time for every desire. Perhaps tomorrow he will want the opposite. If so, his toil was for his evil!
Ibn Ezra: Since everything depends on times, what benefit is there to all one's toil? Perhaps the time for destruction of his toil will come, and his wealth will depart, and he will be left empty.
