Now the Torah reverts to present this legislation in greater detail. This is the reason why we are told where these details were first spelled out. What we read here is only a prototype. The principle does not apply only to the sh’mittah legislation, but wherever some legislation had been mentioned in a general manner only, when the details were filled in this took place at Mount Sinai, just as it did in the case of the sh’mittah legislation. (Torat Kohanim 1,1)
The reason that Moses mentioned this particular legislation at this point is because at this time he was still under the impression that the Israelites would proceed in short order to the land of Canaan, the sin of the spies which set them back by forty years not having occurred yet. Even as late as Numbers 10,29 Moses still spoke to the people of the impending journey to the Holy Land. Speaking about the soil of the holy Land “resting,” is the subject in Leviticus 26,34 as well as in Chronicles II 36,21. This shows that the main focus of the sh’mittah legislation concerns the “Sabbatical” experienced by the farmland of the nation.
A YEAR OF SOLEMN REST. Its meaning is, because it is a year of solemn rest for the land; that is, the land is not in your dominion in this year.
3) (Vayikra 25:5) ("The after-growth of your harvest you shall not reap, and the grapes of your guarded vine you shall not glean; a year of rest shall there be for the land.") This is the source for the sages' ban on the after-growths of the seventh year. "and the grapes of your guarded vine you shall not glean": From what is guarded in the land you may not glean, but you may glean from hefker (what you relinquished ownership of.) "you shall not glean": in the (usual) way of the gleaners — whence they ruled: Figs of shevi'ith are not to be cut with the usual tool, but with a knife. Grapes are not to be trod in a vat, but in a kneading trough. Olives are not to be processed in a (bad) (an olive-press) or in a kotiv (a smaller press), but may be crushed and put into a bedidah (a small press). R. Shimon says: They may also be ground in a bad and put into a bedidah.
(ז) הַיּוֹצֵר, מוֹכֵר חֲמִשָּׁה כַּדֵּי שֶׁמֶן וַחֲמִשָּׁה עָשָׂר כַּדֵּי יַיִן, שֶׁכֵּן דַּרְכּוֹ לְהָבִיא מִן הַהֶפְקֵר. וְאִם הֵבִיא יוֹתֵר מִכָּאן, מֻתָּר. וּמוֹכֵר לְנָכְרִים בָּאָרֶץ, וּלְיִּשְׂרָאֵל בְּחוּצָה לָאָרֶץ:
(7) The potter may sell five oil-jars and fifteen wine-jars, for this is the usual amount one collects from ownerless produce. But if he brought more, it is still permitted. He may also sell [more jars] to Gentiles in the land of Israel and to Jews outside of the land.
עלי קנים ועלי גפנים שגיבבן בחבא על פני השדה לקטן לאכילה יש בהן משום קדושת שביעית לעצים אין בהן משום קדושת שביעית ומשני אמר קרא (ויקרא הכ, ו) לאכלה במי שהנאתו וביעורו שוין יצאו עצים שהנאתן אחר ביעורן
With regard to reed leaves and vine leaves that one piled for storage upon the field, if he gathered them for eating, they are subject to the sanctity of the Sabbatical Year; if he gathered them for use as wood, e.g., for kindling a fire, they are not subject to the sanctity of the Sabbatical Year. And Rava answers the contradiction, as the verse states: “And the Sabbath produce of the land shall be for food for you” (Leviticus 25:6), indicating that the sanctity of the Sabbatical Year takes effect only with regard to those items whose benefit and whose consumption coincide, as is the case with regard to food. Wood is excluded, as its benefit follows its consumption.