BabylonianTalmud, Baba Metziah 85b

Raysh Lakish was marking the boundaries of the Rabbis’ burial crypts. When he reached the crypt of R. Chiya, it remained hidden from him. He became upset, and declared: “Master of the Universe! Have I not analyzed the Torah as profoundly as he [R. Chiya]?” A voice came forth from heaven and told him: “You have analyzed Torah as profoundly as he, but you did not disseminate Torah to the extent that he has!” Once, when R. Chanina (bar R. Chama) and R. Chiya disagreed, R. Chanina said to R. Chiya: “Do you dare argue with me?!” If, Heaven forbid, the Torah were to be forgotten from the Jewish people, I would be able to restore it through my incisive analytic abilities!” R. Chiya retorted: “Do you dare argue with me?!” I make sure that the Torah will never be forgotten from Israel! What do I do? I go and plant flax seed. Then (after harvesting the flax) from that flax I weave nets in which I trap deer. I feed the deer meat to orphans and I make the deer skins into parchment upon which I write the five Books of the Torah. Then I go up to a village where there are no teachers, and I teach each of five children how to read one of the books of Torah, and I teach (orally) each of six other children one of the six orders of the Mishnah. Then I say to them: ‘During the time that I go home and then return here, teach the Five Books of Torah to one another and teach Mishnah to one another.’ In this manner, I make sure that the Torah will never be forgotten from Israel.” This is what Rebbe was referring to when he declared: “How great are the deeds of Chiya!” [Soncino translation]