The 231st mitzvah is that we are commanded to bury those who have been executed by the High Court on the same day of their execution.
The source of this commandment is G‑d's statement1 (exalted be He), "[You may not allow his body to remain on the gallows overnight,] you must certainly bury him on the same day."
The Sifri2 says, "The phrase, 'You must certainly bury him' is a positive commandment."
This law applies to all deceased; every Jew should be buried on the day in which he passes away. This is the reason why a person who has nobody to arrange his burial is called a "meis mitzvah." This means that he is a meis (dead person) for which the mitzvah is on every individual to bury. [The mitzvah referred to is] G‑d's statement (exalted be He), "You must certainly bury him [on the same day]."
The details of this mitzvah are explained in the 6th chapter of tractate Sanhedrin.3
