Surah At-Taubah (The Repentance), Verse 125

وَاَمَّا الَّذِیْنَ فِیْ قُلُوْبِهِمْ مَّرَضٌ فَزَادَتْهُمْ رِجْسًا اِلٰی رِجْسِهِمْ وَمَاتُوْا وَهُمْ كٰفِرُوْنَ ۟

Wa ammal lazeena fee quloobihim maradun fazaadat hum rijsan ilaa rijsihim wa maatoo wa hum kaafiroon

“But those in whose hearts is a disease,- it will add doubt to their doubt, and they will die in a state of Unbelief.”

Quran 9:125 (Yusuf Ali Translation)