The underlying reason for Shemitat Ksafim?

Question

I've researched the topic for a while and I could not find a single interpreter discussing the reason (טעם המצווה) for canceling loans after the Shemitah Year.

I know it is a Machloket (see my previous question) whether the loans are canceled or just forbidden to claim, but for the sake of this question, I'll take Rambam's and Shu"A's views that the money is LOST.

"אין שביעית משמטת כספים אלא בסופו לפיכך הלוה את חבירו בשביעית עצמה גובו חובו כל השנה בב"ד וכשתשקע חמה בליל ר"ה של מוצאי שביעית אבד החוב:"

• We know it is a DeOraytah Mitzvah

• We know that the Torah is extremely stringent on Gezel and money misjudgments, like Ribbit, Honaah etc. Kabbalah adds some frightening details on reincarnations and post-mortem suffering caused by such monetary misbehavior.

• A person does a Mitzvah lending his money to his fellow in a sincere hope to receive it back.

• Despite the fact that Shemitat Ksafim is linked to returning of the land after Yovel, there's a huge difference - the land is never sold forever, only for a certain amount of years until the Yovel, but a person can lend his money for a week and then 6 years later the debt is miraculously canceled.

• The Torah does not differentiate for different types of borrowers - rich or poor - all loans are canceled. They do not turn into a Tzedakkah either. So it's hard to claim a socialistic claim of equality and justice.

I would like to sincerely understand the heavenly reason for justice that is made in this Mitzvah.

Answer 1

The Sefer Hachinuch in Mitzvah 477 says that the main reasons for this Mitzvah are in order to instill a sense of compassion in the person foregoing the loan, as well as to help train him to have more faith in God.

כבר כתבתי במשפטים במצות שמטת קרקעות (מצוה פד), מה שידעתי בשרש המצוה, ושמיטת כספים גם כן, אחר אותו הטעם נמשך, ללמד נפשנו במדות מעלות מדת הנדיבות ועין טובה, ולקבע בלבבנו הבטחון הגדול בשם ברוך הוא, ואז תכשר נפשנו לקבל טוב מאת אדון הכל כלול בברכה והרחמים, וגם נמצא מזה גדר חזק ומחיצה של ברזל להתרחק מאד מן הגזל ומן החמדה בכל אשר לרענו, כי נשא קל וחמר בנפשותינו לאמר אפילו הלויתי ממוני והגיע שנת השמטה אמרה תורה להשמיט ביד המלוה שלא לגזל ושלא לחמד משלו לא כל שכן שראוי לי להתרחק עד הקצה האחרון?

I have already written in Mishpatim on the commandment of the release of lands (Sefer HaChinukh 84) that which I have known about the root of the commandment; and the release of monies also draws from the same reason - to train our souls in the virtuous traits, the trait of generosity and a kind eye, and to fix great faith in our hearts towards God, blessed be He. And then our soul will be prepared to receive the good from the Master of all, which is included in blessing and mercy. And also coming from this is a strong fence and partition to distance oneself greatly from theft and from envy for everything that there is to our neighbor. As we will draw an a fortiori argument (kal vechomer) for ourselves by saying, "Even with my money that I lent out, the Torah said to release it in the hand of the borrower when the sabbatical year arrives; is it not all the more so that with not stealing and not having envy for that which is his, that it is fitting for me to distance myself to the [other] extreme?"

Rabeinu Avraham ben Harambam also says a similar idea regarding developing a sense of compassion about halfway through the fifth chapter of Hamaspik Leovdai Hashem (translation from the Feldheim edition):

As mentioned earlier, all of the mitzvos concerning the rights of the poor enable us to cultivate generosity and compassion, as well as the trait of abstinence. These are the mitzvos of [...] and keeping the laws of the seventh year regarding produce and loans, as well as the laws of the fiftieth year.

While ultimately, the true underlying reason why we keep Shemitah and any other Mitzvah is because Hashem commanded us to, we see at least 2 Rishonim who believed that an additional motivation for the Mitzvah of Shemittah was to help cultivate our sensitivity and compassion for others.

Answer 2

In general, there seems to be a theme of Israel and its land never being enslaved in perpetuity, specifically not for more than six units (days/years depending on the context), corresponding to the six days of creation of the physical universe.

כִּֽי־לִ֤י בְנֵֽי־יִשְׂרָאֵל֙ עֲבָדִ֔ים עֲבָדַ֣י הֵ֔ם אֲשֶׁר־הוֹצֵ֥אתִי אוֹתָ֖ם מֵאֶ֣רֶץ מִצְרָ֑יִם אֲנִ֖י ה' אֱ-לֹקיכֶֽם׃

For it is to Me that the Israelites are servants: they are My servants, whom I freed from the land of Egypt, I am the LORD your God. (Leviticus 25:55)

Israel being subjugated for more than six would represent a denial of its transcendent mission, i.e. of rising above the physical. Thus, Israel is forbidden from working for more than six consecutive days (Shabbat) and its land is forbidden from being worked for more than six years (shemitta).

Similarly, based on the biblical principle of "עָ֭שִׁיר בְּרָשִׁ֣ים יִמְשׁ֑וֹל וְעֶ֥בֶד לֹ֝וֶ֗ה לְאִ֣ישׁ מַלְוֶֽה" - "The rich rule the poor and the borrower is a slave to the lender" (Proverbs 22:7), debts, which are considered a form of servitude, are canceled after the shemitta year.