What is the significance of a Letz seeking Chachmah?
Rashi: When he needs Chachmah, he does not find it in his heart.
R. Yonah: A Letz (a) engages in idle talk, and (b) mocks people, their deeds and words. This Midah requires annulling fear and casting off the yoke. These two Midos distance him from Chachmah. Chachmah is not found in those who sit in corners and love idleness. It is found only in those who learn with fear, and not in scoffers who annul fear. 'Chachmah that I learned with Af (anger), it stood for me 1 .' 'Instill Marah (fear) in Talmidim (Kesuvos 103b), 'any Chacham whose lips do not drip with Mar (bitterness, due to awe), his lips should be burned!' (Shabbos 30b).
Malbim: A Letz mocks the laws of Chachmah, for there is no proof for them. They are received. One must receive them with humility and Emunah. A Letz does not mock Da'as, which is known via proofs or the senses. He cannot reach it. If he would understand the laws of Chachmah with a clarity called Da'as, he would not scoff! A Letz is not a Kesil or Evvil who argues with the laws of Chachmah due to heresy or desire. Rather, he scoffs and does not accept them because he does not understand them. However, he cannot understand them because one must accept them with Emunah. When he seeks Chachmah, he does not find it, for he mocked it and did not accept it.
Yalkut Shimoni (Koheles 968). Kli Yakar (Bereishis 45:24): This is because anger always leads to a mistake. One understands a Halachah only if he stumbled in it first (Gitin 43a)! "U'Mitz Af Yotzi Dam" (below 30:33) -- if a Talmid is silent when his Rebbi gets angry at him the first time, he merits to distinguish between Tahor blood and Tamei blood (Brachos 63b). Torah Temimah (Koheles 2(40)) - "Af Chachmasi" is what I learned amidst anger of my Rebbi. Chachmah u'Musar (1:214) - what I learned with exertion, it is considered mine.
What is the significance of "v'Da'as l'Navon Nakal"?
R. Yonah: There are three levels - Chachmah, Tevunah and Da'as. Da'as is the greatest. [Even] the first, Chachmah, the Letz cannot get it; Da'as, the highest, is easy for the Navon. From Binah he comes to Da'as. He habituates his heart to clarify true De'os and distance the mistaken ones. Only a Navon will attain Da'as - 'if there is no Binah, there is no Da'as' (Avos 3:17).
Malbim: It is hard for a Chacham to come to Da'as, i.e. to know the ways of Chachmah as clearly as one knows things that are sensed. However, a Navon - after investigating the laws of Chachmah to understand their reasons, and understanding a matter amidst another matter, it is easy for him to reach Da'as of them.
