Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 33
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 33, with English translation by Maimonides (Rambam).
שלא לנחש, שנאמר "לא תנחשו" (ויקרא יט,כו).
Not to act as a soothsayer, as [Leviticus, ibid.] states: "Do not act as a soothsayer."