The Heights - 7:37
"Who is more unjust than he who slanders Allah or denies His signs? Their portion as described in the Book will reach them. When Our messengers come to them and take their lives: "Where are those whom you used to serve besides Allah?"they say, "They have forsaken us."They bear witness against themselves that they were disbelievers."
While the messengers take the lives of those who slander Allah falsely:
The Cattle/6:93
"Who is more unjust than he who fabricates a lie in the name of Allah and says, "I am being revealed to me,"when nothing has been revealed to him, and says, "I will send down what Allah has sent down, as Allah has sent down"! Behold the wrongdoers in the hour of their agony! The angels stretch out their hands: "Give your lives! You will be punished this day with a shameful torment for saying what is not true about Allah and for your arrogance and pride in His signs (revelation and miracles). "