Negative commandment · Lo Ta’aseh #110 of 613
Not to sell a field that has been dedicated
שלא למכור שדה החרם
The verse · Vayikra 27:28
אַךְ־כׇּל־חֵרֶם אֲשֶׁר יַחֲרִם אִישׁ לַה׳ מִכׇּל־אֲשֶׁר־לוֹ מֵאָדָם וּבְהֵמָה וּמִשְּׂדֵה אֲחֻזָּתוֹ לֹא יִמָּכֵר וְלֹא יִגָּאֵל כׇּל־חֵרֶם קֹדֶשׁ־קׇדָשִׁים הוּא לַה׳
“Notwithstanding no devoted thing, that a man shall devote to the Lord of all that he has, both of man and beast, and of the field of his possession, shall be sold or redeemed: every devoted thing is most holy to the Lord.”
The Rambam’s words
Not to sell a field that has been dedicated, as [Leviticus 27:28] states: "It shall not be sold."
שלא למכור שדה החרם, שנאמר "לא יימכר" (ויקרא כז,כח).
Why · Sefer HaChinuch #358
That owners that dedicated land not sell it, but that it rather be given to the priests
“It is from the roots of the commandment [that it is] because Israel is the nation that G-d chose from all the other nations for His service and to recognize His Name, and they are not under the rule of the constellations that G-d apportioned to all the other nations.”
Where in the Mishneh Torah
Hilchot Appraisals and Devoted Property הלכות ערכים וחרמין