Musar על בבא מציעא 169:20

And they said, in the chapter entitled "The hiring of workers" (Baba Mezi'a 85a and see Rashi) : When R. Zera emigrated to Palestine he fasted forty days (some texts read 100 fasts) to forget the Babylonian Talmud, that it should not trouble him. And they said : If a man stumbled by committing a sin for which the penalty is death by the decree of Heaven, what should he do so that he may live? If he was accustomed to read one page of the Talmud let him read two pages, if he was accustomed to repeat a chapter once let him repeat it twice, if he was accustomed to study one chapter let him study two chapters (Lev. Rabbah 25:1). We thus see that study is the principal thing, for if sharp debate were the principal thing, to cry out and to raise one's voice half a day over one statement, then he should have said, "If previously he was accustomed to raise one objection let him raise two objections."