Negative commandment · Lo Ta’aseh #310 of 613
Not to allow a sorcerer to live
שלא להחיות מכשף
The verse · Shemot 22:17
מְכַשֵּׁפָה לֹא תְחַיֶּה
“Thou shalt not suffer a witch to live.”
The Rambam’s words
Not to allow a sorcerer to live, as [Exodus 22:17] states: "Do not allow a witch to live."
שלא להחיות מכשף, שנאמר "מכשפה, לא תחייה" (שמות כב,יז).
Why · Sefer HaChinuch #62
To not keep a witch alive
“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 this commandment to administer the laws of those that do magic is practiced by males — since it is fitting [for] and it was given to them to administer justice — and not females.”
Where in the Mishneh Torah
Hilchot The Sanhedrin and the Penalties within Their Jurisdiction הלכות סנהדרין והעונשין המסורין להם