Leviticus 24:14-16

14‘Take the man outside the camp. All the people who heard him speak must put a hand on him. All the people must throw stones at him until he is dead.

15Tell Israel's people, “It is a sin if any man says bad things about God's name.

16He must die. All the people must throw stones at him until he is dead.” You must kill anyone who says bad things about the Lord's name. They may be a foreigner or an Israelite. You must kill them.