Leviticus 24
15 Ref And say to the children of Israel, As for any man cursing God, his sin will be on his head.
16 Ref And he who says evil against the name of the Lord will certainly be put to death; he will be stoned by all the people; the man who is not of your nation and one who is an Israelite by birth, whoever says evil against the holy Name is to be put to death.