This law is repeated here, either to justify this sentence of putting blasphemers to death, from the same severity executed for a less crime; or to prevent the mischievous effects of men's striving or contending together, which as here it caused blasphemy, so it might in others lead to murder.
Related Commentaries of Leviticus 24:17
Leviticus 24:17
17 And he that killetha any man shall surely be put to death.