Pirkei Avos, Mishnah 1 (with Hebrew)

Moses received the Torah at Sinai and transmitted it to Joshua, Joshua to the elders, and the elders to the prophets, and the prophets to the Men of the Great Assembly. They said three things: Be patient in [the administration of] justice, raise many disciples and make a fence round the Torah.

Moshe received the Torah from Sinai: I say: Since this tractate is not founded on the exegesis of commandments from among the Torah’s commandments, like the rest of the tractates which are in the Mishna, but is rather wholly morals and principles, and whereas the sages of the (other) nations of the world have also composed books according to the fabrication of their hearts, concerning moral paths, how a person should behave with his fellow; therefore, in this tractate the tanna began "Moshe received Torah from Sinai," to tell you that the principles and morals which are in this tractate were not fabricated by the hearts of the Mishna’s sages; rather, they too were stated at Sinai.

Moshe received the Torah from Sinai and transmitted it to Yehoshua: Both the written Torah and the oral Torah. As the Torah was given with its explanation. As if it were not so, it would be impossible to understand [its contents]. As behold, it is written (Leviticus 19:13), "do not rob" - and all of the [laws of] damages are within this negative commandment, and they themselves are the Torah that was received by Moshe at Sinai, even though they were not written. And it is also written (Deuteronomy 17:8), "between a blood and a blood and between a judgement and a judgement and between an infection and an infection" - and many of the sightings of blood and many of the various judgments and so many of the infections are known to us by the transmission [of this information]... And they are not explained [in writing] because it is not allowed to be written. And it is written (Exodus 24:12), "and I will give you the stone tablets and the Torah and the commandment" - "Torah" is the written Torah; "and the commandment" is the oral Torah. it comes out that you say that every commandment that He gave to Moshe at Sinai, was given with its explanation. And that which is written is what is called the written Torah and the explanation is what is called the oral Torah. And Moshe learned it from the mouth of the Mighty One.

and the Elders to the Prophets, and the Prophets transmitted it to the Men of the Great Assembly: And that is Ezra and his group. And [some of] the prophets of the Second Temple were in that group, as they said in Yevamot 16a, "Rabbi Dosa ben Harkinas said, 'When Chaggai said these three things, he was sitting on this mortar.'" Hence the prophets of the Second Temple were there after the destruction, since Haggai the prophet was there. And the men of the Great Assembly transmitted it to the men of their generation. And the sages [transmitted it] to their children after them in each and every generation. And the transmission was from one sage to another, until all of the sages of Israel gathered and a suggestion was given from all of their mouths to write down the oral Torah. And [so] they wrote and sealed the Talmud, and afterwards nothing was added to it and nothing was taken away from it. And that generation also transmitted it to the Geonim and the transmission was from one Gaon to another, one rabbi to another - until this day.

raise up many disciples: As per the opinion of Beit Hillel. [This is] like the matter that we have learned (The Fathers According to Rabbi Nathan 2:9), "Beit Shammai say, 'We only teach a student who is fit, modest, proper and who fears Heaven, as it is stated (Job 20:26), "All (darkness) waits for his treasured ones." And Beit Hillel say, 'We teach everyone: One hundred so that ten good ones will come out from them; and ten so that two will come out of them; and two, "since you do not know which will be proper, this one or that one or if they will both be equally good." And so was there a story of Hillel, who brought together all of his students and said to them, 'Are all of you here?' They said [back] to him, 'Yes.' One of his students said to him, 'All of them are here except the smallest one.' He said to them, 'Let the small one come, for the future generation will be conducted by him .' And they brought Rabban Yochanan ben Zakkai. Behold that one should not push off the small ones for the bigger ones, since the kids will become goats." And about this matter the rabbis, may their memory be blessed, expounded (Yevamot 62b), "'Sow your seed in the morning, and don’t hold back your hand in the evening' (Ecclesiastes 11:6), - if you have raised disciples in your youth, raise disciples in your old age." Behold that the multiplication of disciples is a very good thing and a merit to the teacher.

they stated three things: They stated many things; rather, they said these three things because they contain within them the preservation of the Torah.

"Be discerning in judgment": Where if a case comes before you one, two or three (times), do not say "This case already came before me, and (I ruled) a second and a third time." Rather, "Be discerning," which is to say deliberate before you decide the case.