Dear Rabbi Kornfeld: When the gemara brings the statements of amoraim which are ethical drashas, are these drashas that have a mesora back to Har Sinai on those pesukim, or are they the ethical drashas of the amoraim themselves? For example, the kolos at Har Sinai corresponding to the five kolos (Brachos daf vav, amud beis). Thanks.
David,
From Nazir 4b it seems that at least sometimes, when we learn an ethical teaching from a verse, it cannot be used to teach us a Halachah afterwards, since it is already "used up" (the verse in question is "Nazir l'Hashem").
However, often such teachings are no more than an Asmachta, which does not actually "use up" the verse but rather bases the moral lesson on the verse as a "reminder" for the moral lesson. Apparently, Derech Eretz Kadma l'Torah, which means that one is expected to act ethically even had the Torah not specifically told him so. Therefore, the TOrah has to teach us a mode of behavious only when it is not obvious in its own right that such is the proper way to behave.
BE well, and excuse me for the delay in response,
-Mordecai