What is "v'Sabosi"?
Rav Sadya Gaon: I returned.
Ibn Ezra: It is like one who turns his face to another direction.
What is the meaning of "Leya'esh [Es Libi]"?
Rashi: [I despaired from, i.e. decided] not to exert and toil.
Ibn Ezra: It is to go in the opposite path. This is Pi'el conjugation from the root Ya'ash. The middle letter should have a Dagesh; it does not, for it is guttural (Aleph). This is like "v'No'ash Mimeni Sha'ul" (Shmuel I, 27:1).
Ri Kara: I did not have Simchah [over my toil, for I will leave my acquisitions to others].
Seforno: I ceased to hope that in the merit of my Chachmah, I will merit to leave my acquisitions to a Chacham, who will use them to perfect his Nefesh, and I will merit with him (because I aided him).
Metzudas David: This is a metaphor. I ceased to be concerned for my heart [and hated it, for it enticed me to toil and gather acquisitions.