Negative commandment · Lo Ta’aseh #159 of 613
For a priest not to marry a chalalah
שלא ייקח כוהן חללה
The verse · Vayikra 21:7
אִשָּׁה זֹנָה וַחֲלָלָה לֹא יִקָּחוּ וְאִשָּׁה גְּרוּשָׁה מֵאִישָׁהּ לֹא יִקָּחוּ כִּי־קָדֹשׁ הוּא לֵאלֹהָיו
“They shall not take a wife that is a harlot, or profaned; neither shall they take a woman put away from her husband: for he is holy to his God.”
The Rambam’s words
For a priest not to marry a chalalah, as [Leviticus 21:7] states: "They shall not marry... a chalalah."
שלא ייקח כוהן חללה, שנאמר "וחללה לא ייקחו" (ויקרא כא,ז).
Who & when
“And [it] is practiced in every place and at all times.”
Where in the Mishneh Torah
Hilchot Forbidden Intercourse הלכות איסורי ביאה