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Surah 9. Al-Tawba
Ayah 80
80 ٱسْتَغْفِرْ لَهُمْ أَوْ لَا تَسْتَغْفِرْ لَهُمْ إِن تَسْتَغْفِرْ لَهُمْ سَبْعِينَ مَرَّةً فَلَن يَغْفِرَ ٱللَّهُ لَهُمْ ۚ ذَٰلِكَ بِأَنَّهُمْ كَفَرُوا۟ بِٱللَّهِ وَرَسُولِهِۦ ۗ وَٱللَّهُ لَا يَهْدِى ٱلْقَوْمَ ٱلْفَـٰسِقِينَ
80. Whether you (O Muhammad ) ask forgiveness for them (hypocrites) or ask not forgiveness for them -- (and even) if you ask seventy times for their forgiveness -- Allah will not forgive them because they have disbelieved in Allah and His Messenger. And Allah guides not those people who are rebellious.
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,
("What is you name) He said, "Al-Hubab bin `Abdullah.'' The Prophet said,
(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,
(Allah said,(...(and even) if you ask seventy times for their forgiveness...) Verily, I will ask Allah to forgive them seventy times and seventy more and seventy more.)'' Similar narrations were collected from `Urwah bin Az-Zubayr, Mujahid, Qatadah bin Di`amah and Ibn Jarir.