Musar su Ecclesiaste 9:16

The wise man said, "He who speaks with wisdom and intelligence, it is like salt to a cooked dish." And there is charm in the words of the wise like a ruby in a setting of gold. But "the poor man's wisdom is despised, and his words are not heard" (Eccl. 9:16). This being the case, let him put his words in the mouth of a wise man or a rich man in order that they may be heard, while he himself is silent.

And thus did our Rabbis interpret the text, "The poor man's wisdom is despised" (Eccl. 9:16). What wisdom of what poor man is despised? It refers to a man who is poor in good deeds; then his wisdom is despised. And if one teaches laws that instruct us to do good and he himself does not do good deeds his words are not accepted, for "not learning but doing is the chief thing" (Aboth 1:17). Wherefore it is necessary tor every man to direct his deeds for the sake of Heaven and see and understand from the example of Elisha, the son of Abuyah : because his father taught him Torah not for its own sake, the son turned to heresy. As it is said in the Jerusalem Talmud (Hagigah 2:1), and in the Midrash (Eccl. Rabbah 7:8, letter 18) : When Elisha, the son of Abuyah was circumcised his father made a feast for the Sages and invited Rabbi Eiezer and Rabbi Joshua and the other Sages, and they sat at the feast and spoke words of the Torah to the extent that a fire came and encircled them. The father of Elisha came and said to them, "My good friends, did you come to burn down the house?" And they said to him, "The fire that you see is only because we are studying the words of the Torah and the Prophets and the Scriptures. And the words of our discussion joyously testify to the truth just as when they were given at Mount Sinai. From Mount Sinai were they given, and from the fire were they given!" The father of Elisha ben Abuyah then said, "Now that I see the power of the Torah, if this my son will live on, I shall give him to the study of Torah." And because the father had it in his mind that he would teach his son Torah not for its own sake but for the power it would give him, his son became a heretic. And even so, a man should study the Torah even if not for its own sake, because from studying it not for its own sake, he will ultimately come to study it for its own sake (Pesahim 50b).