"You shall not kindle fire throughout your settlements on the Shabbat day"—Exodus 35:3.
It is forbidden for the courts to administer punishments on Shabbat. The Sages interpreted the above verse as an injunction against executing a criminal via burning (one of the four methods of capital punishment employed by the courts) on Shabbat—and the same rule applies to all other forms of capital punishment. From this verse the Sages also extrapolated the prohibition against holding any court proceedings on Shabbat.
