Musar על שבת 125:4

He who is truly a servant of G-d, will not be satisfied with serving Him minimally. He will not be content to take silver mixed with dross and lead, that is, divine service mixed with impure motivations, but rather only with the clean and pure as is befitting. Then he will be called "one who does a mitzva as it is stated", of which our sages of blessed memory said: "whoever does a mitzva as it is stated, will receive no evil tidings" (Shab.63a). Likewise they said: "do [good] deeds for the sake of their Maker, and speak of them for their own sake" (Nedarim 62a).

Thus it was in the land of France that they occupied themselves with great industry and much time, and they would sit in one place to study all of the Talmud, and they would constantly review, and the Torah did not cease from their mouths. And they did according to the deeds of the earlier Sages, as they said, "Let one by all means learn, even though he is liable to forget, yea, even if he does not fully understand all of the words which he studies" (Abodah Zarah 19a). And they said, "That a man should study and subsequently understand." And all of this they do not do now, for everyone wants to study Tosafot, and new interpretations before he knows even the structure of the Talmud. This being the case, how can they make any progress? For they do the opposite of what the Sages of the Talmud said, for everything that is said in the Talmud is all true and one ought not to take issue with it or change it, nor add to it nor subtract from it.