Commentary for Pirkei Avot 1:16

RABBAN GAMLIEL SAID. He was the grandson of Hillel, as the Talmud says in Shabbat 15a: Hillel, Simon, Gamliel, and Simon were the nesi’im for the last hundred years that the second temple stood. The commentators explain that the reason the mishna no longer introduces each tanna with the phrase “he received the tradition from so-and-so” is that starting from the students of Hillel and Shammai, numerous unresolved legal disputes arose in Israel, and the Torah became as two Torahs. It is therefore no longer possible to say they “received” the Torah, because the Torah of each sage could no longer be said to have been definite, received and transmitted as was the Torah of the earlier sages.
But I feel that for this reason alone the tanna would not have rejected the term “received,” for they did indeed receive the main foundations of Torah, where there was no disagreement whatsoever, as Rambam writes at length in the introduction to his commentary on the Mishna. And in point of fact the question is moot, because in 2:8 the mishna says “Rabban Yochanan ben Zakai received the tradition from Hillel and Shammai.”

Rabban Gamliel says, "Make for yourself a mentor, remove yourself from doubt": He means to say that he should take his colleague as his mentor - even though he is not more wise than he, and even if he has not even reached [the first one's] wisdom - in order that he remove himself from doubt. And in Talmud Yerushalmi Moed Katan 1:10, it states, "Go and bring me an elder from the marketplace and I will rely upon him and permit [it] to you." As there are times when a sage will be in doubt about a ruling and he will not know what to say: If he permits, maybe it is forbidden and a mishap will occur through him; and if he forbids what is permitted, it will come out that he will cause a loss of money to Israel, whereas the Torah is concerned about it. Therefore, he should make his colleague a mentor and ask him about his questions. And he will make the ruling upon his mouth, even if the matter is simple to him and even if it is a permissive ruling, even when he is not as great as he in wisdom. And thus did the Geonim say, "In anything where it is a doubt to one and clear to the other, the law is like the one to whom it is clear, even [if it is] a student before his mentor."

Rabban Gamliel says, "Make for yourself a mentor, remove yourself from doubt and do not frequently tithe by estimation." That which he commanded here to make a mentor is not regarding study, but rather legal decisions: place for yourself a mentor, that you can rely upon in the forbidden and the permissible, and you can remove yourself from doubt. [It is] as they say in Talmud Yerushalmi Moed Katan 1:10, "Go and bring me an elder from the marketplace and I will rely upon him and permit [it] to you." And so [too] did he command to flee from putting out tithes by estimation, because it is from the doubts.

Rabban Gamliel: And he was the grandson of Hillel. And therefore was there no expression of receiving written from here on – since disagreement increased in Israel from the time of the students of Shammai and Hillel, etc. [and the Torah] was not defined and received and transmitted as it was with the earlier ones. So did the commentators explain. And this is not indisputable, as in Chapter 2, Mishnah 8, we learned, “Rabban Yochanan ben Zakkai received, etc... from Hillel and Shammai, etc."

”Make for yourself a mentor:”: It is now speaking concerning the matter of jurisdiction. If a case comes in front of you and you are in doubt about it, make for yourself a mentor, and remove yourself from doubt. And do not decide upon it by yourself; as it was with Rava: when a possibly unfit animal was brought to him, he would gather all of the slaughterers of Mata Machsia – he would say, “So that we will [all only] receive a chip of the beam."

Introduction After completing the teachings of the “pairs” Mishnah Avoth turns to the teachings of the patriarchs, the leaders of the Jewish people who were from the family of Hillel. Rabban Gamaliel of our mishnah is Rabban Gamaliel the elder, who was the grandson of Hillel. He was the patriarch during the final years of the Second Temple. He is also the first who is called by the title “Rabban” a title reserved (with one exception) for the patriarchs from Hillel’s family. Another interesting thing to note is that almost all of the remainder of Avoth does not use the terminology “received from him/them”. While this change in terminology in the mishnah is certainly significant, it is hard to know exactly what the significance is. One thing is clear: Rabban Gamaliel, the first person to be called Rabban, and the first person in Avoth not to “receive”, opens a new era in the history of the Oral Torah.

AND DO NOT FREQUENTLY TAKE OFF MA`ASER BY ESTIMATE. Rav writes: because when one takes off ma`aser by estimating, he cannot escape wrongdoing. If he takes off less than he should, then his ma`aser is valid but the rest of the produce is unfit, and if he takes off more than he should, the rest of his produce is fine but the ma`aser is unfit. Rambam explains in Hilchot Ma`aser 1:14 that the ma`aser is unfit because it is mixed with tevel. So also Rashi in his commentary to the second chapter of tractate Kiddushin, on page 51a (s.v. hamarbeh). And in his commentary to the fourth chapter of tractate Eruvin, on page 50a (s.v. perotav), he adds “unlike terumah, which has no set amount.” See also Rav's commentary to the mishna in Terumot 4:6.
Midrash Shmuel writes in the name of R. Yosef ibn Shoshan the Pious: it seems odd that the mishna does not simply say “do not take off ma`aser by estimate” and entirely forbid taking of ma`aser without a proper measure. I say, then, that the mishna means that even one who wishes to take off more than the required amount shouldn’t do so because he might err in his estimate.⁴⁵Midrash Shmuel (and Tosafot mentioned after) will then read the verb in the mishna, al tarbeh, as “do not take off more,” as opposed to “do not frequently take off,” which has been the meaning assumed until this point. And Tosafot in their commentary to Gittin 31a (s.v. nitelet) conclude that the mishna only forbids intentionally taking off more than the required amount, based on the mishna in Terumot 4:6: he who takes off by weight is more praiseworthy than the three of them, which implies that there are three legitimate ways to take off ma`aser, one of which must be by estimate.<sup>46</sup>The mishna there only lists two other ways: by count and by measure. Tosafot conclude that there must be a third way that was not mentioned, which they say is by estimate. So also Rav in his commentary there: we see that even the Sages did not forbid taking off by estimate when one doesn’t intentionally take off more. But according to Rambam, as I mentioned earlier, it would be forbidden even without this intention, and Rash in his commentary on Terumot agrees.
The Maharal in his Derech Chaim explains the mishna as following the opinion of Abba Eliezer ben Gomel, who holds that even terumat ma`aser, which has a set amount, may be taken off by estimate; he would certainly say the same about ma`aser [and the Talmud in fact says as much in Bechorot 59a, as Rav notes in his commentary to Bechorot 9:7]. For this reason the mishna says “do not frequently etc.”, which is to say even though the Torah allows taking off ma`aser by estimate, do not do so often, in order to save yourself from doubt. And the word ma`asarot in the mishna does not exclude terumat ma`aser, because ma`asarot here is a general name for all types of priestly gifts taken from the produce of the earth, as I have shown from the Jerusalem Talmud in my commentary to Ma`asarot 2:4. See also my comments on Demai 4:1.
But I see that Rash writes in his commentary to Terumot 1:7 that it seems that Abba Eliezer ben Gomel does not hold of the injunction “do not often take off ma`aser by estimate,” and this is the opinion of Tosafot on the abovementoined passages in Gittin and Bechorot.

"and do not frequently tithe by estimation": That he not tithe his fruits by estimation. If he wants to tithe what he has measured out generously [to be] more than the tenth, it comes out that [that which is beyond the tenth] is [still] tevel (a forbidden mixture that requires separation to render it permissible) that is not tithed until he puts his eyes to it to tithe it, and it comes out that there is a corruption of this tithe. And this matter is a metaphor for the matter of reasoning, in which a person should not do it by estimation, but rather in the way of principles and to come to full knowledge. And this is not the case with all reasonings. As there is one that is nuanced and the sage - even though his reasoning leans to the side that he understands - recognizes that another sage can [see] it in a different way. It is just that [his way] looks more [correct] in his eyes. And there is [another] reasoning that a sage innovates and recognizes and knows that it is logically correct and necessary, has no other angles and that no other sage would disagree. And the one who understands will understand [this]. And for this [reason] was this matter made adjacent to [the teaching], "Make for yourself a mentor, remove yourself from doubt" - as [the two teachings] are [based on] almost the same rationale.

Since untithed produce is mixed in with them - [Rambam] and Rashi. And the pious Rabbi Y. Ibn Shoshan wondered why he did not completely forbid to tithe except by measuring: "And let it say, 'Do not tithe by estimation.' What is [meant by] 'do not frequently (literally, increase)?' And therefore I say that the intention is that even if you intend to increase the tithes and to give more than the measure [it it forbidden], lest you err in your estimate." And see Tosafot Yom Tov.

"and do not frequently tithe by estimation": as the one who separates his tithes by estimation is not spared from disarray: if he reduces from what needs to be given, his tithes are made adequate but his fruit are disarrayed; if he adds upon what is fitting to give, his fruits are rendered adequate and his tithes are disarrayed.

Rabban Gamaliel used to say: appoint for thyself a teacher, avoid doubt, and do not make a habit of tithing by guesswork. The first statement of Rabban Gamaliel is the same statement taught by Rabbi Joshua ben Perahiah, in mishnah six. “Avoid doubt” means that if a person should be confronted by a doubtful halachic case, for instance he doesn’t know whether something is pure or impure, he should not decide for himself, but rather he should ask a higher authority, a rabbi whose knowledge is greater. For if the person says that something is impure and it was really pure, he will cause a financial loss to the owner. And if he says it was pure and it was really impure, he will cause someone to transgress. Note how this statement connects to the previous one. In order to avoid doubt a person must have a teacher. Before one eats his produce he must give two tithes. The first tithe goes to the Levite and the second tithe must either be consumed in Jerusalem (during the 1st, 2nd, 4th and 5th years of a Sabbatical cycle) or be given to the poor (during the 3rd and 6th years). Rabban Gamaliel teaches that one should not tithe by estimate, but rather should make sure that his tithes are precise. This also connects with the previous statement, that one should avoid doubt. If one tithes by estimate, his food is considered “doubtfully tithed produce”, which is forbidden. This final statement is also understood by commentators as meaning that a person should not make any halachic decisions by guesswork. Rather he should carefully check his sources to make sure that his decision is not only reasonable, but correct.