Musar על בבא מציעא 170:6

Chazal bring down that when Rebbi Chananiya and Rebbi Chiya debated, Rebbi Chananiya said to Rebbi Chiya, “Would you content with me if, heaven forbid, the Torah were forgotten from Yisrael that I would return it with my sharp intellect? Rebbi Chiya said to Rebbi Chananiya, “Would you content with me that my labour for Torah has insured that it will never be forgotten from Yisrael. What did I do? I went and sowed flax, twisted nets, trapped deer, fed the flesh to orphans, made parchment from their skin, wrote the five books of the Torah, went to a town and taught five children the five books, taught six children the six orders of the Mishna, and I said to them, 'Until I return, teach each other and review with each other.' And my labour for Torah has insured that it will never be forgotten from Yisrael.” And, on this, Rebbi said, “How great is this act of Chiya” (Bava Metziya 85b).