viz.: Three mitzvot (commandments)h are stated in this context, two ("You shall not kill" and "You shall not commit adultery") and one ("You shall not steal") ambiguous. Just as the explicit are mitzvoth punishable by judicial death penalty, so, the ambiguous must be a mitzvah punishable by judicial death penalty. You cannot understand it, then, as per the second option (i.e., You shall not steal money), but as per the first (i.e., You shall not kidnap.) This, (our verse, then, must be an exhortation against stealing a soul, and the other, an exhortation against stealing money.