The 229th mitzvah is that we are commanded to execute by stoning1 those who transgress certain mitzvos.
The source of this mitzvah is G‑d's statement2 (exalted be He), "They shall be put to death by stoning." I will point out the mitzvos which are punishable by stoning when listing the prohibitions.
The details of this mitzvah are explained in the 6th chapter of tractate Sanhedrin.