Ruach chaim avos 6:3 explains that dovid hamelech learned from achitofel who was ein lo chelek lolam haboh and creates a kale vchomer... but achitofel rebelled against dovid at during the avshalom rebellion and promptly committed suicide. Wasn't a achitofel still raui (or at least not in geder of ein lo chelek) when dovid hamelech learned from him?
Moshe Rubin, Brooklyn, New York
Dear Moshe,
Suggestion: The Gemara in Chagigah 15b says that Shmuel cried: How can it be that Doeg and Achitofel were so great in Torah knowledge but in the end had no Olam ha'Ba? Rebbi Yehudah answered him that they had "Tina" in their hearts; Rashi explains that they were wicked "from their days" -- meaning throughout their lives.
The Gemara seems to be saying that their Torah was never Torah as it should be and did not lift and protect them. From our Gemara we see that David ha'Melech still honored Achitofel.
All the best,
Reuven Weiner