Surah An-Nisa — Ayah 48 (4:48)
إِنَّ ٱللَّهَ لَا يَغۡفِرُ أَن يُشۡرَكَ بِهِۦ وَيَغۡفِرُ مَا دُونَ ذَٰلِكَ لِمَن يَشَآءُۚ وَمَن يُشۡرِكۡ بِٱللَّهِ فَقَدِ ٱفۡتَرَىٰٓ إِثۡمًا عَظِيمًا ٤٨
English translation (Saheeh International)
Indeed, Allāh does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allāh has certainly fabricated a tremendous sin.
Brief commentary
Allah does not forgive that anything from His creation should be associated to Him. Besides this and disbelief, He pardons the disobedience of whomever He wills, out of His bounty. Or He punishes those He wills among them according to their disobedience, out of His perfect justice. Whoever worships others next to Allah has committed a terrible sin, which is not forgiven if someone dies still doing it.