Surah Al-An'am — Ayah 21 (6:21)
وَمَنۡ أَظۡلَمُ مِمَّنِ ٱفۡتَرَىٰ عَلَى ٱللَّهِ كَذِبًا أَوۡ كَذَّبَ بِـَٔايَٰتِهِۦٓۚ إِنَّهُۥ لَا يُفۡلِحُ ٱلظَّٰلِمُونَ ٢١
English translation (Saheeh International)
And who is more unjust than one who invents about Allāh a lie or denies His verses? Indeed, the wrongdoers will not succeed.
Brief commentary
The greatest wrongdoer is the person who attributes a partner to Allah and worships him together with Allah, or the person who denies Allah’s words that He revealed to His Messenger. Those who do wrong by ascribing partners to Allah and denying His verses will never succeed if they do not repent.