תניא היה רבי מאיר אומר הלומד תורה ואינו מלמדה זה הוא דבר ה' בזה רבי נתן אומר כל מי שאינו משגיח על המשנה ר' נהוראי אומר כל שאפשר לעסוק בתורה ואינו עוסק
It is taught in a baraita that Rabbi Meir would say: With regard to one who studies Torah and does not teach it to others, this person is included in the category of: “He has despised the word of the Lord,” as his conduct indicates that he does not consider the word of God significant enough to teach others. Rabbi Natan says: Anyone who does not pay the requisite attention to the Mishna and does not consider it essential halakha is included in the category of: “Because he has despised the word of the Lord.” Rabbi Nehorai says: Anyone for whom it is possible to engage in Torah study and who nevertheless does not engage in its study is included in the category of: “Because he has despised the word of the Lord.”
רַבִּי יִשְׁמָעֵאל בְּנוֹ אוֹמֵר, הַלּוֹמֵד תּוֹרָה עַל מְנָת לְלַמֵּד, מַסְפִּיקִין בְּיָדוֹ לִלְמֹד וּלְלַמֵּד. וְהַלּוֹמֵד עַל מְנָת לַעֲשׂוֹת, מַסְפִּיקִין בְּיָדוֹ לִלְמֹד וּלְלַמֵּד לִשְׁמֹר וְלַעֲשׂוֹת. רַבִּי צָדוֹק אוֹמֵר, אַל תַּעֲשֵׂם עֲטָרָה לְהִתְגַּדֵּל בָּהֶם, וְלֹא קַרְדֹּם לַחְפֹּר בָּהֶם. וְכָךְ הָיָה הִלֵּל אוֹמֵר, וּדְאִשְׁתַּמֵּשׁ בְּתָגָא, חָלָף. הָא לָמַדְתָּ, כָּל הַנֶּהֱנֶה מִדִּבְרֵי תוֹרָה, נוֹטֵל חַיָּיו מִן הָעוֹלָם:
Rabbi Ishmael his son said: He who learns in order to teach, it is granted to him to study and to teach; But he who learns in order to practice, it is granted to him to learn and to teach and to practice. Rabbi Zadok said: do not make them a crown for self-exaltation, nor a spade with which to dig. So too Hillel used to say, “And he that puts the crown to his own use shall perish.” Thus you have learned, anyone who derives worldly benefit from the words of the Torah, removes his life from the world.
י֗וֹם אֲשֶׁ֨ר עָמַ֜דְתָּ לִפְנֵ֨י יְהֹוָ֣ה אֱלֹהֶ֘יךָ֮ בְּחֹרֵב֒ בֶּאֱמֹ֨ר יְהֹוָ֜ה אֵלַ֗י הַקְהֶל־לִי֙ אֶת־הָעָ֔ם וְאַשְׁמִעֵ֖ם אֶת־דְּבָרָ֑י אֲשֶׁ֨ר יִלְמְד֜וּן לְיִרְאָ֣ה אֹתִ֗י כׇּל־הַיָּמִים֙ אֲשֶׁ֨ר הֵ֤ם חַיִּים֙ עַל־הָ֣אֲדָמָ֔ה וְאֶת־בְּנֵיהֶ֖ם יְלַמֵּדֽוּן׃
The day you stood before the LORD your God at Horeb, when the LORD said to Me, “Gather the people to Me that I may let them hear My words, in order that they may learn to revere Me as long as they live on earth, and may so teach their children.”
יִלְמְדוּן. יֵלְפוּן – לְעַצְמָם:
יִלְמְדוּן — The Targum is יֵלְפוּן, “They shall learn" (more lit., the action reverts to themselves), while —
יְלַמֵּדוּן. יְאַלְּפוּן – לַאֲחֵרִים:
יְלַמֵּדוּן the Targum is יְאַלְפוּן, “They shall teach" (more lit., the action reverts to others).
אָמַר רַבִּי חָמָא בְּרַבִּי חֲנִינָא מַאי דִּכְתִיב בַּרְזֶל בְּבַרְזֶל יָחַד לוֹמַר לָךְ מָה בַּרְזֶל זֶה אֶחָד מְחַדֵּד אֶת חֲבֵירוֹ אַף שְׁנֵי תַּלְמִידֵי חֲכָמִים מְחַדְּדִין זֶה אֶת זֶה בַּהֲלָכָה
The Gemara cites other expositions that deal with Torah study. Rabbi Ḥama, son of Rabbi Ḥanina, said: What is the meaning of that which is written: “Iron sharpens iron, so a man sharpens the countenance of his friend” (Proverbs 27:17)? This verse comes to tell you that just as with these iron implements, one sharpens the other when they are rubbed against each other, so too, when Torah scholars study together, they sharpen one another in halakha.
אָמַר רַב נַחְמָן בַּר יִצְחָק לָמָּה נִמְשְׁלוּ דִּבְרֵי תוֹרָה כְּעֵץ שֶׁנֶּאֱמַר עֵץ חַיִּים הִיא לַמַּחֲזִיקִים בָּהּ לוֹמַר לָךְ מָה עֵץ קָטָן מַדְלִיק אֶת הַגָּדוֹל אַף תַּלְמִידֵי חֲכָמִים קְטַנִּים מְחַדְּדִים אֶת הַגְּדוֹלִים וְהַיְינוּ דְּאָמַר רַבִּי חֲנִינָא הַרְבֵּה לָמַדְתִּי מֵרַבּוֹתַי וּמֵחֲבֵירַי יוֹתֵר מֵרַבּוֹתַי וּמִתַּלְמִידַי יוֹתֵר מִכּוּלָּן
Rav Naḥman bar Yitzḥak said: Why are Torah matters likened to a tree, as it is stated: “It is a tree of life to them who lay hold upon it” (Proverbs 3:18)? This verse comes to tell you that just as a small piece of wood can ignite a large piece, so too, minor Torah scholars can sharpen great Torah scholars and enable them to advance in their studies. And this is what Rabbi Ḥanina said: I have learned much from my teachers and even more from my friends, but from my students I have learned more than from all of them.