At-Taubah - 9:80

اسْتَغْفِرْ لَهُمْ أَوْ لاَ تَسْتَغْفِرْ لَهُمْ إِن تَسْتَغْفِرْ لَهُمْ سَبْعِينَ مَرَّةً فَلَن يَغْفِرَ اللّهُ لَهُمْ ذَلِكَ بِأَنَّهُمْ كَفَرُواْ بِاللّهِ وَرَسُولِهِ وَاللّهُ لاَ يَهْدِي الْقَوْمَ الْفَاسِقِينَ
[9:80]
Ask forgiveness for them or do not ask forgiveness for them; even if you ask forgiveness for them seventy times, Allah will not forgive them; this is because they disbelieve in Allah and His Messenger, and Allah does not guide the transgressing people.
Whether thou ask for their forgiveness, or not, (their sin is unforgivable): if thou ask seventy times for their forgiveness, Allah will not forgive them: because they have rejected Allah and His Messenger: and Allah guideth not those who are perversely rebellious.
Ask forgiveness for them (O Muhammad), or ask not forgiveness for them; though thou ask forgiveness for them seventy times Allah will not forgive them. That is because they disbelieved in Allah and His messenger, and Allah guideth not wrongdoing folk.