The blasphemous ones think that if the Prophet is true in his claim to be the Messenger of ALLAH, why ALLAH is not punishing us for the insult of HIS Messenger! ALLAH says that Hell-fire will be a suitable punishment for such morally bankrupt people, so HE is not sending on them any torment right now, for no punishment on this earth will be enough for their blasphemy. And so we should wait for the Day of Dooms to let ALMIGHTY settle the score with them. Another narration of slandering I found in Chapter 9/61
“And among your opponents there are such as blaspheme the Prophet by saying, ‘HE puts ears to all the sayings'. Say O Prophet: ‘listening to all is in your good'. Our Prophet puts his trust in ALLAH, and trusts the believers, and the Prophet is ALLAH's grace for those who has attained to faith. And as for those who malign ALLAH's Messenger - grievous suffering of Hell-fire awaits for them in the life to come!"
(From Holy Qur'an 9/61)
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