Negative commandment · Lo Ta’aseh #337 of 613
Not to have intimate relations with a woman and her daughter
שלא לגלות ערוות אישה ובתה
The verse · Vayikra 18:17
עֶרְוַת אִשָּׁה וּבִתָּהּ לֹא תְגַלֵּה אֶת־בַּת־בְּנָהּ וְאֶת־בַּת־בִּתָּהּ לֹא תִקַּח לְגַלּוֹת עֶרְוָתָהּ שַׁאֲרָה הֵנָּה זִמָּה הִוא
“Thou shalt not uncover the nakedness of a woman and her daughter, neither shalt thou take her son’s daughter, or her daughter’s daughter, to uncover her nakedness; for they are her near kinswomen: it is foulness.”
The Rambam’s words
Not to have intimate relations with a woman and her daughter, as [Leviticus 18:17] states: "Do not commit incest [by marrying] a woman and her daughter."
שלא לגלות ערוות אישה ובתה, שנאמר "ערוות אישה ובתה, לא תגלה" (ויקרא יח,יז).
Who & when
“And this prohibition is practiced in every place and at all times.”
Where in the Mishneh Torah
Hilchot Forbidden Intercourse הלכות איסורי ביאה