Avot330

1:
Our mishnah continues the series which is based on the number 4, and also the sub-series which is concerned with four types regarding various religious activities. Our present mishnah is concerned with the Bet Midrash.

2:
In Tannaïtic times the Bet Midrash was the place where a sage met with his students and taught his Torah. The Bet Midrash may have been inside a synagogue or it may even have been in an open field. But to the Bet Midrash of such-and-such a sage, wherever it might be, would repair all those who wished to learn Torah from his lips. Generally speaking, the student would choose the teacher rather than the Bet Midrash. Thus if the teacher at whose feet one wished to study lived and taught far from where one lived one would leave home and go to stay in the place where that particular sage lived and taught. And one would stay there for however long it took. When we studied Tractate Yadayyim we made a very long excursus in which we studied several examples of would-be sages who spent years away from home and family while studying in the Bet Midrash. It is worth reviewing that material here.

3:
It is very tempting, of course, to explain our present mishnah in terms of our contemporary experience. Were we to do so we would understand that the first type was someone who studied Judaism but didn't practice it, that the second type referred to someone who observed the practices of Judaism but did not engage in Torah studies – and so with the other types. But such an explanation would do a grave injustice to the intentions of our mishnah, and we must take another tack.

4:
Rambam, in his commentary on our mishnah, points out that it is not concerned with the learning capabilities of the students (which is the subject of the next mishnah). It is concerned with four types of "going" to the Bet Midrash. It is concerned with motivation rather than achievement.

5:
The first type "goes but does not do". In his commentary on our present mishnah Rabbi Ovadya of Bertinoro explains that this means that

We have mentioned so often that learning in the Tannaitic period required constant repetition of what one has learned orally, that it requires no further elaboration here. [See Avot 172, for example.] This explains who it comes about that in the Gemara very often a statement is challenged by the quotation, one after the other, of a whole series of dicta which contradict that statement. All these come from material that was learned.

6:
Quite often the sages would refer to the time spent by a student with his teacher, far from home, as "exile". The student was, in fact, uprooting himself from his natural milieu in order to learn Torah. In Avot 254 we saw one Tanna actually recommending:

But not everyone was prepared to undertake such an upheaval. Many decided to study Torah at home, presumably with a local sage whose acumen and fame may have been lacking compared with the great ones of the age. Our mishnah notes that while such a student has certainly lost by his decision, he has not lost out entirely: even if he has not reaped the rewards that 'exiling' oneself offered he will nevertheless reap the reward of studying Torah. Whereas the former "has the reward for going" the latter "has the reward for doing."

7:
The saint depicted in our mishnah not only 'exiles' himself to a place of Torah, but he repeats what he has learned again and again so that it is embedded in his memory and he becomes a living repository of what he has learned from his teacher. The student who is a sinner, of course, neither takes the trouble to go and learn from a renowned teacher nor does he even bother to repeat what he has learned from the teacher that he did choose. The former both "goes and does" while the latter "neither goes nor does".