Surah An-Nisa' (The Women), Verse 48

اِنَّ اللّٰهَ لَا یَغْفِرُ اَنْ یُّشْرَكَ بِهٖ وَیَغْفِرُ مَا دُوْنَ ذٰلِكَ لِمَنْ یَّشَآءُ وَمَنْ یُّشْرِكْ بِاللّٰهِ فَقَدِ افْتَرٰۤی اِثْمًا عَظِیْمًا ۟

Innal laaha laa yaghfiru ai yushraka bihee wa yaghfiru maa doona zaalika limai yashaaa'; wa mai yushrik billaahi faqadif taraaa isman 'azeemaa

“Allah forgiveth not that partners should be set up with Him; but He forgiveth anything else, to whom He pleaseth; to set up partners with Allah is to devise a sin Most heinous indeed.”

Quran 4:48 (Yusuf Ali Translation)