Negative commandment · Lo Ta’aseh #186 of 613
Not to cook meat and milk [together]
שלא לבשל בשר בחלב
The verse · Shemot 23:19
רֵאשִׁית בִּכּוּרֵי אַדְמָתְךָ תָּבִיא בֵּית ה׳ אֱלֹהֶיךָ לֹא־תְבַשֵּׁל גְּדִי בַּחֲלֵב אִמּוֹ
“The first of the firstfruits of thy land thou shalt bring to the house of the Lord thy God. Thou shalt not boil a kid in its mother’s milk.”
The Rambam’s words
Not to cook meat and milk [together], as [Exodus 23:19] states: "Do not cook a kid in its mother's milk."
שלא לבשל בשר בחלב, שנאמר "לא תבשל גדי, בחלב אימו" (שמות כג,יט; שמות לד,כו; דברים יד,כא).
Why · Sefer HaChinuch #92
To not cook meat in milk
“From the roots of the commandment are that it is known that magic is a very bad thing and causes many mishaps to people. I do not have to write at length about it, as the things are well-known.”
Who & when
“And [it] is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Forbidden Foods הלכות מאכלות אסורות