Myse: A young man, a student of Rav Moshe Feinstein ztz"l, was once in Rav Moshe's house leafing through a sefer. He was impressed with the sharpness and novel thoughts of the author and mentioned the sefer to Rav Moshe. Rav Moshe said that you can't rely on his chiddushim because he was of very faulty character. The student asked how that can be when he has haskamos on the sefer from luminaries of the previous generation. Rav Moshe replied that all they wrote was that the author is a genius but they said nothing about his character.
Years later this very same student was found doing terrible things and had to leave his distinguished position in disgrace.
Li-myse:
1] Why did Rav Moshe have to speak disparagingly about this author? Why couldn't he let him be. He was long gone anyway?!
Rav Moshe had impeccable middos. He just understood that we must know which rabbis are reliable and which are not. This applies today as well. MOST rabbis are very fine human beings but there is a small percentage of rotten apples out there who are mechalel shem shomayim. It is important to know who they are in order to know not to follow them.
2] Toras Emes emanates not only from great minds but great hearts as well. If a person is just a genius and can razzle dazzle but lacks Yiras Shomayim - beware. Rabbeinu Yonah writes as much in his commentary to Avos - The Torah only truly dwells in a body of pure middos. Otherwise he is just a חמור נושא ספרים. Lots of knowledge but the possessor is but a donkey.
3] This young student later ignominiously lost his job and stature. He knew better. He was a close enough talmid of Rav Moshe to be in his apartment looking through sefarim and schmoozing with the gadol hador. He was/is a lamdan. What happened that he fell? I don't know:-). But I DO know that אין אפוטרופוס לעריות and people have to be exceedingly careful.
