Musar su Proverbi 30:10

In the preceding chapters we spoke about the individual. How much more so must one take great heed not to impute liability to Israel in general, for this sin is very severe. As we find in Pesachim 87b on Proverbs 30:10 "'Speak not ill of a servant to his master… a generation that curses its father and does not bless its mother.' …Even a generation that curses its father and does not bless its mother — do not speak ill of it to its Master — the Holy One Blessed be He." And see now [the instance of] Isaiah the prophet. When he saw the glory of the L-rd and said (Isaiah 6:5): "Woe unto me, for I am lost, for I am a man of unclean lips; and in the midst of a people of unclean lips do I dwell, etc." — because he said "and in the midst of a people of unclean lips," even though his intent in this was not to shame Israel, (for he said this also of himself) but only to say that he was not worthy of seeing the Shechinah, neither in point of his deeds nor of those of the people in whose midst he dwelt — in spite of this, see what follows (Ibid. 6): "Then one of the seraphs flew unto me [Isaiah] and in his hand was a live coal [ritzpah]," concerning which Chazal say that "ritzpah" is acronymic of "retzoth peh" ["crush the mouth"] that slanders My children." And he died as a result of this, as they say in Yevamoth 49b: "[He (Isaiah) uttered the Name and was 'swallowed up' in a cedar.] the cedar was brought and sawed. When it [the saw] came to his mouth, he died, [this, for having said 'And in the midst of a people of unclean lips do I dwell.']"