הררי קדם חלק ב' סימן קכב
(א) ... וּקְטַנִּים פְּטוּרִים מִתַּלְמוּד תּוֹרָה. אֲבָל קָטָן אָבִיו חַיָּב לְלַמְּדוֹ תּוֹרָה שֶׁנֶּאֱמַר (דברים יא יט) "וְלִמַּדְתֶּם אֹתָם אֶת בְּנֵיכֶם לְדַבֵּר בָּם".
(1) ... and infants are absolved from the study of the Torah; but the father is obliged to instruct his infant son in the Torah, for it is said: "And ye shall teach them your children, talking of them" (Deut. 11.19);
(ב) כְּשֵׁם שֶׁחַיָּב אָדָם לְלַמֵּד אֶת בְּנוֹ כָּךְ הוּא חַיָּב לְלַמֵּד אֶת בֶּן בְּנוֹ שֶׁנֶּאֱמַר (דברים ד ט) "וְהוֹדַעְתָּם לְבָנֶיךָ וְלִבְנֵי בָנֶיךָ". וְלֹא בְּנוֹ וּבֶן בְּנוֹ בִּלְבַד אֶלָּא מִצְוָה עַל כָּל חָכָם וְחָכָם מִיִּשְׂרָאֵל לְלַמֵּד אֶת כָּל הַתַּלְמִידִים אַף עַל פִּי שֶׁאֵינָן בָּנָיו. שֶׁנֶּאֱמַר (דברים ו ז) "וְשִׁנַּנְתָּם לְבָנֶיךָ" מִפִּי הַשְּׁמוּעָה לָמְדוּ בָּנֶיךָ אֵלּוּ תַּלְמִידֶיךָ שֶׁהַתַּלְמִידִים קְרוּיִין בָּנִים שֶׁנֶּאֱמַר (מלכים ב ב ג) "וַיֵּצְאוּ בְנֵי הַנְּבִיאִים". אִם כֵּן לָמָּה נִצְטַוָּה עַל בְּנוֹ וְעַל בֶּן בְּנוֹ. לְהַקְדִּים בְּנוֹ לְבֶן בְּנוֹ וּבֶן בְּנוֹ לְבֶן חֲבֵרוֹ:
(2) Even as man is obliged to instruct his son, so is he obliged to teach his son's son, for it is said: "But make them known to thy sons and thy sons' sons" (Ibid. 4.9); and, not alone to his son and his son's son, but each and every scholar in Israel is commanded to instruct all who desire to be his disciples, even though they be not his sons, for it is said: "And thou shalt teach them diligently unto thy children" (Ibid. 6.7.), which is traditionally interpreted to include one's disciples; for disciples, too, are called children, as it is said: "And the sons of the prophets came forth" (Second Kings, 2.3.). If it be so, why then was one commanded to teach his son and his son's son? To permit the precedence of one's son to one's son's son, and his son's son to the son of his fellow.
אמר ריב"ל כל המלמד את בן בנו תורה מעלה עליו הכתוב כאילו קבלה מהר סיני שנאמר והודעתם לבניך ולבני בניך וסמיך ליה יום אשר עמדת לפני ה' אלהיך בחורב (דברים ד, י)
(ג) וְחַיָּב לִשְׂכֹּר מְלַמֵּד לִבְנוֹ לְלַמְּדוֹ. וְאֵינוֹ חַיָּב לְלַמֵּד בֶּן חֲבֵרוֹ אֶלָּא בְּחִנָּם.
(3) One is obliged to engage a teacher for the instruction of his son; but his fellow's son he is not obliged to teach, save when there is no expense to himself.
... ואפשר דלדעת רבינו גם לבן בנו חייב לשכור לו מלמד...
... and it's possible that according to our Master (the Rambam) even for a grandchild one is obligated to hire a teacher.
(א) שנמנענו שלא נשכח מעמד הר סיני ולא נסיר אותו מדעתנו אבל יהיה עינינו ולבנו שם כל הימים. והוא אמרו יתעלה השמר לך ושמור נפשך מאד פן תשכח את הדברים אשר ראו עיניך ופן יסורו מלבבך כל ימי חייך והודעתם לבניך ולבני בניך יום אשר עמדת לפני ה' אלהיך בחורב וגו'. והכונה בזאת גדולה מאד שאם היו דברי תורה באים אצלנו מפי הנביא עליו השלום בלבד אע"פ שנתאמת אצלנו ענין נבואתו באותות ומופתים אם יקום בקרבנו נביא או חולם חלום בזמן מן הזמנים ויצונו בשום דבר הפך מן התורה ונתן אלינו אות או מופת תהיה התורה נצוחה על יד השני או יכנס בלבנו ספק על זה, אבל כשהגיענו ביאור התורה מפי הגבורה לאזנינו ועינינו רואות אין שם אמצעי נכחיש כל חולק וכל מספק לא יועילהו אות ולא יצילהו מידינו מופת, שאנחנו היודעים ועדים בשקרותו ובפחזותו, זה הוא שנאמר במעמד ההוא וגם בך יאמינו לעולם, והוא הענין הבא בפרשת כי יקום בקרבך נביא או חולם חלום וגו', וכבר ביאר הרב זה בספר המדע, והוא יסוד גדול בתורה והוא המניעה הבאה לנו בפסוק פן תשכח את הדברים אשר ראו עיניך והזהיר פן יסורו מן הלב מהודיעם לבנים ולבני בנים לדורות עולם, ואל תטעה בזה מפני דרשם בפירקא קמא דקידושין (דף ל') לבניך ולבני בניך בלימוד התורה לבני בנים, כי לימוד אמונת התורה הוא הלימוד בתורה, אבל נתבונן ונקח ראיה מדבריהם כי היא מצוה עולמית ועם כל הדורות ידבר בלא ישכחו ענין המעמד ההוא שהיה לכל אדם למראית עיניהם ושמיעת אזניהם ושיעתיקו זה מדור לדור לעולם. וזאת המצוה זכרה בעל הלכות גדולות ג"כ והרב שכחה:
(1) The second mitzvah [that the Rambam “forgot” to include in his Book of Mitzvot] is that we have been warned to never forget standing at Har Sinai, and to never remove this event from our consciousness. Rather, our eyes and our hearts should be directed there all of the days. It is as the Exalted One said, “Be careful, and guard your soul greatly, lest you forget the things that your eyes saw and lest they leave your heart all the days of your life. And you shall make them known to your children and their children - the day that you stood before Hashem your G-d at Chorev, etc.” (Devarim 4:9-10). The intent in this [commandment] is of tremendous importance. For if the words of Torah were to come upon us only from the mouth of the prophet, peace be upon him, then even if his prophecy was demonstrated to us to be truthful with signs and with wonders, if at some later point in time a prophet or dreamer would arise and command us to do something which was against the Torah, providing signs and wonders [to support his words], the Torah would be removed by the second [prophet], or [at the very least] an uncertainty could enter our hearts over this issue. However, once the explanation of the Torah arrived to our ears from the Mouth of G-d and our eyes saw that there was no intermediary, we will refute any who argue or present doubt and we will demonstrate his falseness. Signs won’t benefit him, nor will any wonder save him from our hands. For we will recognize and testify to his falsehoods and recklessness. This is the meaning of the statement regarding the gathering at Sinai, “And in you [Moshe] they shall always believe.” (Shemot 19:9). This is[also] the meaning of the passage, “If a prophet or dreamer shall rise up amongst you etc.” (Devarim 13:2). The master [Rambam] has already explained his in the Book of Knowledge (The Foundations of the Torah, Chapter 8). And this is a critical foundation of the Torah and is the prohibition that comes to us from the verse, “lest you forget the things that your eyes saw.” It is a warning lest they leave your heart, such that you will not don’t convey them to your children and their children through all of the generations. And don't err based on the [Rabbi's] expounding in the first chapter of Kiddushin (Daf 30) that "To your children and your children's children" teaches the mitzva of teaching Torah to one's children's children; because teaching belief in the Torah is itself the teaching of Torah. On the contrary, we should understand and see evidence from their words that this is an eternal mitzva and that [Moshe] is addressing all generations about not forgetting the significance of that event which was visible to every person's eyes and audible to their ears and that they should transmit it from generation to generation for ever. This mitzva was included by the Ba'al Halachot Gedolot as will, but [the Rambam] the Master forgot it.
- Teaching them Torah, based on the pasuk ולמדתם אותם את בניכם.
- Teaching them belief in the Torah, based on the pasuk והודעתם לבניך ולבני בניך, which is also a fulfilment of the negative commandment of not forgetting מעמד הר סיני.
As it was taught in a baraita: It is written: “And you shall impart them to your children and your children’s children” (Deuteronomy 4:9), and it is written thereafter: “The day that you stood before the Lord your God at Horeb” (Deuteronomy 4:10). Just as below, the Revelation at Sinai was in reverence, fear, quaking, and trembling, so too here, in every generation, Torah must be studied with a sense of reverence, fear, quaking, and trembling [and not levity associated with an emission].
However, the second component, of conveying the experience of Matan Torah and the belief in it, is best achieved by grandfather teaching grandson, as the grandfather is closer to the generation of Sinai, and this is what is expressed by the Gemara in Kiddushin, focusing on the juxtaposition of teaching grandchildren and מעמד הר סיני.
(ד) הָיָה הוּא רוֹצֶה לִלְמֹד תּוֹרָה וְיֵשׁ לוֹ בֵּן לִלְמֹד תּוֹרָה הוּא קוֹדֵם לִבְנוֹ. וְאִם הָיָה בְּנוֹ נָבוֹן וּמַשְׂכִּיל לְהָבִין מַה שֶּׁיִּלְמֹד יוֹתֵר מִמֶּנּוּ בְּנוֹ קוֹדֵם. וְאַף עַל פִּי שֶׁבְּנוֹ קוֹדֵם לֹא יִבָּטֵל הוּא. שֶׁכְּשֵׁם שֶׁמִּצְוָה עָלָיו לְלַמֵּד אֶת בְּנוֹ כָּךְ הוּא מְצֻוֶּה לְלַמֵּד עַצְמוֹ:
(4) One who was ambitious to pursue learning, and, at the same time, has a son whom he is obliged to instruct, his own study comes first; if his son be diligent and intellectually more capable to grasp his studies than himself, his son comes first. Nevertheless, he shall not completely abandon his own study, his son's precedence notwithstanding; for, even as he is commanded to teach his son, so is he under command to study himself.
Rav Soloveitchik argues that this indicates that there is a distinction to be drawn between the basic chiyuv (obligation) of Talmud Torah and its higher kiyum (fulfilment / desired outcome). The basic chiyuv gives precedence to teaching oneself over teaching one's children (assuming one's children are not of greater ability). It gives priority to both of these over teaching one's children's children.
However, the psukim indicate that the highest kiyum of Talmud Torah is to teach others (ושננתם לבניך, ולמדתם אותם את בניכם, והודעתם לבניך ולבני בניך) and it is clear that from this perspective teaching one's children is superior to one's own learning. Presumably, in this respect, teaching one's grandchildren is also superior to teaching one's children, because one is passing Torah down to future generations. That is why Chazal in Kiddushin say that teaching one's grandchildren is valued by the Torah as if one received the Torah from Har Sinai, because this is the ultimate fulfilment of Talmud Torah. Ma'amad Har Sinai was intended to be an experience of revelation to the entire Jewish people that would be passed down from one generation to the next, and this person is achieving this very goal.
In this vein, Rav Soloveitchik related an incident that took place in Brisk, where there was a father and a son who both required the services of a melamed. It is clear from the above halacha in the Rambam, that the father should take precedence unless the child possesses greater skill and abililty in learning. Nevertheless, Reb Chaim Soloveitchik (the Brisker Rav, Rav Soloveitchik's grandfather) ruled that the son should take precedence. He explained his reasoning that he knew the nature of the father well, and he was aware that even if the father learnt a great amount of Torah, it wouldn't be within the range of his ability to pass it on to future generations or to others. He understood that the Rambam's prioritising the learning of the father only applied if he would then be able to pass on the Torah to future generations. However, if the son is superior in passing on Torah to future generations, it was obvious that he should have precedence. This accords well with what we have seen above, including the notion that study of Torah is actually a fulfilment of the fundamental notion of Talmud Torah, which is the teaching of Torah to the Jewish people.