Why does it say "Sifsei Tzadik Yir'u Rabim"?
Rashi: Many eat due to his merit and his prayer 1 .
R. Yonah: There are many leaders and counselors on the good path.
Malbim: Lips refer to external speech. Leshon Tzadik - he contemplates for himself the path that he will choose for himself. Pi Tzadik is in matters of Chachmah - they are a source of life (11). Sifsei Tzadik are what he says - words that he is used to them. They 'graze' Rabim - he teaches to them his ways.
Brachos 17b: The entire world is fed in the merit of R. Chanina ben Dosa.
Why will Evilim die b'Chasar Lev?
R. Yonah: They do not conduct also themselves, they do not understand their end. Also, they do not accept the Tzadik's conduct and rebuke. His folly will not depart from him until the day of his death.
Malbim: Evvil is unsure about the ways of Chachmah. It is the opposite of Da'as, hinted at in Sifsei Tzadik. Lips imply what is known clearly. Not only does he lack a clear knowledge to say the ways of Chachmah to teach others - also himself he does not graze. He will die b'Chasar Lev, for he has no heart to rule and conduct his desires according to the ways of Chachmah and laws, since he is unsure about them.
