Nedarim 37A

הא קא משמע לן דאפילו במקום שנוטלין שכר, על המקרא שרי למשקל, על המדרש לא שרי למשקל.

The Talmud answers: This teaches us that even in a place where one takes payment for teaching, for teaching Bible it is permitted to take payment, but for teaching midrash it is not permitted to take payment.

מאי שנא מדרש דלא ⁠— דכתיב: ״ואתי צוה ה׳ בעת ההיא ללמד אתכם״, וכתיב: ״ראה למדתי אתכם חקים ומשפטים כאשר צוני ה׳״, מה אני בחנם ⁠— אף אתם נמי בחנם. מקרא נמי בחנם!

The Talmud asks: In what way is midrash different from Bible, that one may not take payment for teaching it? Based on that which is written, which Moses said to the people: “And YHWH commanded me at that time to teach you statutes and laws” (Deuteronomy 4:14), and also that which is written: “Behold, I have taught you statutes and laws, as YHWH my God commanded me, that you should do so in the midst of the land where you go in to possess it” (Deuteronomy 4:5), God said: Just as I teach you for free, without payment, so too you also should teach for free. There should be no difference between Bible and midrash, and Bible too, like midrash, should be taught for free.

רב אמר: שכר שימור. ורבי יוחנן אמר: שכר פיסוק טעמים.

Rav said: As Bible is typically taught to children, one who teaches Bible takes payment for watching the children. And R' Yoḥanan said: He takes payment for teaching punctuation of the text with cantillation notes.

תנן: לא ילמדנו מקרא. בשלמא למאן דאמר שכר פיסוק טעמים ⁠— היינו דלא ילמדנו, אלא למאן דאמר שכר שימור ⁠— גדול בר שימור הוא? בקטן קתני.

We learned in the Mishnah that one for whom benefit from another is forbidden by a vow, that other person may not teach him Bible. Granted, according to the one who says that the payment is for teaching punctuation of the text with cantillation notes, this is the reason that he should not teach him Bible, as teaching punctuation is a component of teaching the biblical text. However, according to the one who says it is payment for watching the students, is an adult one who requires watching, and would payment be taken for doing so? Since the teacher typically does not receive payment for teaching adults, there is no benefit when he teaches for free the one for whom benefit is forbidden; why, then, is it prohibited? The Talmud answers: The Mishnah is teaching about the case of a minor who requires watching and who is prohibited by a vow from deriving benefit from the teacher.