To not steal a soul of Israel: To not steal a soul of Israel, as it is stated (Exodus 20:13), “You shall not steal.” And the explanation comes that the verse is speaking about stealing souls (kidnapping) (Sanhedrin 86a).

The root of the commandment is revealed.

The laws of the commandment — for example, that which they said (Mishneh Torah, Laws of Theft 9:6) [that] there is no difference between an adult and a child or between a man and a woman, as “a soul” implies all cases; the law of a father who steals his son or a master who steals his student; and the rest of its details — are [all] elucidated in Chapter Eleven of Sanhedrin. And its prohibition is practiced in every place and at all times. And one who transgresses it and steals a soul is liable for strangulation, and that is if he has already sold that soul. As so came the explanation (Sanhedrin 85b) that the liability does not rest upon him until he sells; since another verse reveals this, as it is written (Exodus 21:16), “And he steals a man and sells him [...], he will surely be killed.”