Bereishis Rabah (34:10) says that a Tzadik speaks El Libo, and a Rasha speaks b'Libo. Koheles said b'Libo, and also Avraham did (Bereishis 17:17)!
Refer to 2:1:1:1-3 and the note there.
What is the meaning of "Lamah Chachamti"?
Rashi: Why should I be a Tzadik [since I will die just like the Rasha]?
Ibn Ezra: Why did I become wise from my involvement in all worldly matters - "she'Amalti veshe'Chachamti Tachas ha'Shamesh" (19).
What does he call Hevel?
Rav Sadya Gaon, Metzudas David: What I thought, that there was no gain from becoming more Chacham.
Rashi: To think that there was no gain from being a Tzadik.
Ibn Ezra: This Chachmah 1 .
Rid: The advantage of Chachmah over folly.
Seforno: That I became a bigger Chacham than the Kesil.
Chachmah is feminine. It should say Zos or Zu, and not "Zeh"! Perhaps this is why Ibn Ezra said 'Zu ha'Chachmah'. (However, elsewhere he says that a word can be masculine or feminine; he did not say so here. - PF) Magihah in Toras Chayim - here he refers to 'Emel ha'Chachmah' or 'Esek ha'Chachmah.'
