The Torah warns of the hardships – practical and psychological – in observing the practices of Shemitta.
In Parshat Behar, we read of the very real worries that people will suffer from a lack of food:
"And should you ask: What are we going to eat in the Seventh year if we may neither sow nor gather in our crops?" (25:20)
The answer is predicated upon a sense of trust in God:
"I will ordain my blessing for you in the sixth year so that it shall yield a crop sufficient for three years. When you sow in the eighth year, you will still be eating old grain of that crop (of the sixth year)…" (25:21-2)
Likewise, regarding loans, the Torah knows that people will be nervous about lending without the prospect of the loan being repaid:
"Beware lest you harbour the base thought, ' The Seventh Year, the year of remission, is approaching,' so that you are mean to your needy kinsman and give him nothing. He will cry out to God against you, and you shall commit a sin. Give to him readily and have no regrets when you do so for in return, the Lord your God will bless you in all your efforts …" (Devarim 15:9-10)
However despite these divine promises, in the test of history Shemitta always seemed too difficult to observe. Ezra in Sefer Divrei Hayamim records that Shemitta was not observed during the first Temple period (See II Chronicles 36:19-21).
Similarly, At the end of the second Temple period, the great sage Hillel, saw that in the lead-up to Shemitta people were refusing to lend money for fear that the loan would be cancelled. He used a rule that if the loan contract had been given to the court for collection, the loan would not be cancelled. Hillel instituted the "Prozbul," a document which transfers authority for the loan to the courts. Now, the Shemitta year would not annul the loan because the court would reinstate it. Effectively Hillel circumvented the Torah law of loan annulment. Why did he do this? Hillel was faced with a dilemma. On the one hand, the loans were to be annulled. But on the other, this was a measure to protect the poor. Now, the very law that was to protect them was hurting the poor! Nobody would lend them money in the lead-up to the Shemitta. With a heavy heart, Hillel instituted the Pruzbul, ensuring the welfare of the poor but effectively eliminating one of the powerful tools which would activate the communal conscience of Shemitta.
[In contrast, it would appear that the AGRICULTURAL Shemitta was observed during Bayit Sheni despite huge hardship! There is a Midrash which preserves an anti-semitic Roman play. There a camel complains that he is hungry because the Jews ate all his straw and thorns during Shemmitta! In other words, to their credit, the Jews resorted to eating thistles and other wild fruits and foods in order to sustain themselves.]
In our century when the pre-State Yishuv was in its early years, the religious farmers were faced with a tremendous dilemma. They were fighting for every inch of land and barely able to support their families. What should they do about Shemitta? Should they refrain from agriculture during Shemitta, thus effectively abandoning their Kibbutzim and settlements. This would be a major setback for the Zionist cause and was unthinkable. Or should they disregard Shemitta? That too was out of the question. Rav Kook followed Hillel's lead and developed a Halakhic solution that would allow the farmers to continue working the land but circumvent the ban on agricultural labour. (The mechanism here was to sell the land to a gentile for a year - sort of like selling Chametz on Pesach - and Jews are permitted to work the land of a gentile during Shemitta.)
So what has become of the noble vision that Shemitta represents today? Unfortunately, today the utopian image of Shemitta - the equality, the spirituality, the counterbalance to extreme materialism - is nothing but a mirage. Rav Aharon Lichtenstein has spoken of "The tragedy of Shemitta." Today Shemitta has retained certain technical laws but has totally lost its spiritual-social vision.
This Shabbat I asked myself, is it really possible to keep Shemitta in today's world, or in any era? We see that historically we found this enormously difficult. Is it possible to release all loans, and to abandon all agriculture for a year?
How will cities survive with millions of inhabitants. They cannot simply drive to the countryside and pick a few tomatoes for lunch each day!
How does an economy with a stock-market, with bonds, with mortgages with international markets and a global competitive economy, with tight market agricultural allocations - how could we keep shemitta and not rely on these heterim even if we so wished?
Was God's intention to keep our economy on a low-ebb? Was the purpose that the entire country would taste the taste of poverty every seven-year cycle? I don't know, the more I think about Shemitta I find it so difficult to fathom how God envisaged it working?
Maybe some people think that way about Shabbat! How can you just stop for a day?! Is it possible that if we DID do Shemitta in the real sense, we would manage just like we do on shabbat? If we genuinely stopped for a year, and had savings plans (during the six years) that could tide us over and maybe even food stores of grain etc. could it work?
Is Shemitta feasible? I imagine God didn't give us an impossible Mitzva, but historically it has proven formidable, and it looks so impossible!
 ויקרא רבה פרשה א ד"ה א ויקרא אל
(תהלים קג) גבורי כח עושי דברו במה הכתוב מדבר א"ר יצחק בשומרי שביעית הכתוב מדבר
Here the Midrash calls those who observe Shemitta, "Giborim" because it demanded such fortitude.