The 258th prohibition is that we are forbidden from selling a Jewish servant in the manner that non-Jewish servants are customarily sold, i.e. they are stood up in the place singled out for the sale of servants, their sale is publicly announced so that the buyers outbid one another, etc. This is totally forbidden; rather their sale must be done privately and in a refined manner.
The source of this prohibition is G‑d's statement1 (exalted be He), "They shall not be sold as regular servants."
In the words of the Sifra: "The verse 'They shall not be sold as regular servants' prohibits setting up a stand and placing him on the auction stone."
This prohibition undoubtedly includes someone who kidnaps a Jew, since if he sells the kidnapped person, he is selling him in the same way a Canaanite servant is sold — thereby transgressing the prohibition, "They shall not be sold as regular servants." This has already been mentioned above.2 The Written Torah declares that the violator is executed.
The details of this mitzvah and the preceding one3 are explained in the first chapter of tractate Kiddushin.4
