9:80
ٱسْتَغْفِرْ لَهُمْ أَوْ لَا تَسْتَغْفِرْ لَهُمْ إِن تَسْتَغْفِرْ لَهُمْ سَبْعِينَ مَرَّةًۭ فَلَن يَغْفِرَ ٱللَّهُ لَهُمْ ۚ ذَٰلِكَ بِأَنَّهُمْ كَفَرُوا۟ بِٱللَّهِ وَرَسُولِهِۦ ۗ وَٱللَّهُ لَا يَهْدِى ٱلْقَوْمَ ٱلْفَٰسِقِينَ
Ask forgiveness for them, [O Muhammad], or do not ask forgiveness for them. If you should ask forgiveness for them seventy times - never will Allah forgive them. That is because they disbelieved in Allah and His Messenger, and Allah does not guide the defiantly disobedient people.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
The Prohibition of asking for Forgiveness for Hypocrites
Allah says to His Prophet that hypocrites are not worthy of seeking forgiveness for them and that if he asks Allah to forgive them seventy times, Allah will not forgive them. The number seventy here was mentioned to close the door on this subject, for Arabs use this number when they exaggerate, not that they actually mean seventy or more than seventy. Ash-Sha`bi said that when `Abdullah bin Ubayy was dying, his son went to the Prophet and said to him, "My father has died, I wish you could attend him and pray the funeral prayer for him." The Prophet said,
«مَا اسْمُك»
("What is you name) He said, "Al-Hubab bin `Abdullah." The Prophet said,
«بَلْ أَنْتَ عَبْدُاللهِ بْنُ عَبْدِاللهِ إِنَّ الْحُبَابَ اسْمَ شَيْطَان»
(Rather, you are `Abdullah bin `Abdullah, for Al-Hubab is a devil's name.) The Prophet went along with him, attended his father's funeral, gave him his shirt as a shroud and prayed the funeral prayer for him. He was asked, "Would you pray on him, when he is a hypocrite" He said,