All the kinds of blasphemy Allah does not forgive if one dies with it as He, the Exalted, stated in Surah Muhammad, 34:

All the kinds of blasphemy Allah does not forgive if one dies with it as He, the Exalted, stated in Surah Muhammad, 34 :

‎ {إِنَّ الَّذِينَ كَفَرُوا وَصَدُّوا عَن سَبِيلِ اللَّهِ ثُمَّ مَاتُوا وَهُمْ كُفَّارٌ فَلَن يَغْفِرَ اللَّهُ لَهُمْ}

which means: [Surely, those who blaspheme and turn people away from Allah’s way, then they die while they are blasphemers, Allah will never forgive them.]

Explanation

This verse states that Allah will not forgive the one who dies while blasphemous. Death while engaged in blasphemy is a restriction for non forgiveness. In the verse, the meaning of

‎ وَصَدُّوا عَنْ سَبِيلِ اللهِ

is ‘those who turn people away from embracing Islam’. However, this is not a (sole) restriction for the deprivation of forgiveness, rather the blasphemer is deprived from being forgiven whether or not he turned others away from embracing Islam. The blasphemer who turns the people away from embracing Islam is more sinful than the blasphemer who does not.