Avot316

31:
To recap what we have learned so far: Rabbi held that the law concerning shemittah (both the agricultural and the financial shemittah) only applied with all the rigour of Torah law during a period when the law concerning the jubilee was in force. Since the law of the jubilee had fallen into abeyance with the demise of the Northern Kingdom – because 'all Israel' was no longer resident in the land – it followed that in post-biblical times the laws of shemittah did not apply. It follows, therefore, that both Rabbi in the 3rd century CE and his ancestor Hillel 200 years earlier were at liberty to modify the shemittah regulations.

32:
But this raises a basic question: if the laws of shemittah were no longer applicable why was not the whole shemittah system in abeyance? Why was it being observed at all? The Gemara [Gittin 36b] answers this question:

In other words: although the rules and regulations of shemittah no longer had the force of Torah law the sages had decided that we should continue to observe these rules and regulations so that the whole institution of the sabbatical year should not be forgotten in Israel. (Thus when Hillel instituted the Prosbul he was modifying rabbinic law, not Torah law.)

33:
But we should note that Rabbi himself sought to introduce such far-reaching alleviations of the shemittah law that it amounted almost to a complete abolition. One example of his opportunistic method will suffice. It involves an incident that probably occurred during the shemittah year 200 CE.

The Gemara [Ĥullin 6b-7a] records that once Rabbi Me'ir ate a vegetable grown in Bet She'an during a shemittah year and that Rabbi used that precedent in order to declare that Bet She'an was permanently released from the strictures of shemittah, even though it was obviously well within the borders of Eretz-Israel. The opposition to this move was very vocal: "How can you permit something that was expressly prohibited by all your predecessors?" Rabbi dismissed the criticism by claiming that he had a perfect right to act as he had done: "my predecessors have left me room to make a name for myself."

34:
Apparently, Rabbi was of the opinion that in his day and age the rules of shemittah did not apply in all their strictness even from the purely rabbinic point of view. This view was certainly held by many rabbinic authorities in the early middle ages. Many Rishonim maintained that in their day and age shemittah was just middat ĥassidut – an act of supererogation – and no more.

35:
When the first shemittah year came around after the first aliyah to Eretz-Israel (1888) the farmers were in a quandary. Eventually, Rabbi Avraham Kook, the Rav of Yafo, suggested selling the land to avoid the problem of shemittah. He knew that one great luminary of the middle ages, Rabbi Zeraĥyah ha-Levi, had stated categorically that in these times shemittah is just an act of piety, but he thought that this was a lone opinion and therefore should not be relied on too much. However, modern scholarship knows better: many rabbis in Provence and elsewhere considered shemittah in our day and age just an act of piety.

36:
Rabbi David Golinkin has listed the names of some of these sages:

To be continued.