Negative commandment · Lo Ta’aseh #220 of 613
Not to cultivate the land in the seventh year
שלא לעבוד אדמה בשביעית
The verse · Vayikra 25:4
וּבַשָּׁנָה הַשְּׁבִיעִת שַׁבַּת שַׁבָּתוֹן יִהְיֶה לָאָרֶץ שַׁבָּת לַה׳ שָׂדְךָ לֹא תִזְרָע וְכַרְמְךָ לֹא תִזְמֹר
“but in the seventh year shall be a sabbath of solemn rest for the land, a sabbath for the Lord: thou shalt neither sow thy field, nor prune thy vineyard.”
The Rambam’s words
Not to cultivate the land in the seventh year, as [Leviticus 25:4] states: "Do not sow your field."
שלא לעבוד אדמה בשביעית, שנאמר "שדך לא תזרע" (ויקרא כה,ד).
Why · Sefer HaChinuch #326
That we not work the land on the seventh year
“It is from the roots of this commandment to affix in our hearts and make a strong impression in our minds [about] the matter of the world having been created.”
Where in the Mishneh Torah
Hilchot Sabbatical Year and the Jubilee הלכות שמיטה ויובל