Positive commandment · Mitzvat Aseh #136 of 613
Sanctification of the Jubilee year
לקדש שנת יובל בשביתה כשמיטה
The verse · Vayikra 25:10
וְקִדַּשְׁתֶּם אֵת שְׁנַת הַחֲמִשִּׁים שָׁנָה וּקְרָאתֶם דְּרוֹר בָּאָרֶץ לְכׇל־יֹשְׁבֶיהָ יוֹבֵל הִוא תִּהְיֶה לָכֶם וְשַׁבְתֶּם אִישׁ אֶל־אֲחֻזָּתוֹ וְאִישׁ אֶל־מִשְׁפַּחְתּוֹ תָּשֻׁבוּ
“And you shall hallow the fiftieth year, and proclaim liberty throughout all the land to all its inhabitants: it shall be a jubilee for you; and you shall return every man to his possession, and you shall return every man to his family.”
The Rambam’s words
To sanctify the Jubilee year by refraining [from agricultural work], as is done in the shemitah, as [Leviticus 25:10] states: "And you shall sanctify the fiftieth year...."
לקדש שנת יובל בשביתה כשמיטה, שנאמר: "וקידשתם, את שנת החמישים" (ויקרא כה,י).
Why · Sefer HaChinuch #332
Sanctification of the Jubilee year
“It is from the roots of the commandment from the angle of the simple understanding that G-d, may He be blessed, wanted to inform His nation that everything is His; and in the end everything will return to those to whom He wanted to give it at first — for the earth is His, as it is written (Exodus 19:5), “for all the earth is Mine.””
Who & when
“And this commandment is practiced in the Land of Israel at the time that all of its inhabitants (the Jews) are upon it, as I wrote above.”
Where in the Mishneh Torah
Hilchot Sabbatical Year and the Jubilee הלכות שמיטה ויובל