Chapter 9, Verse 80, Repentance
سورة التوبة
ٱسۡتَغۡفِرۡ لَهُمۡ أَوۡ لَا تَسۡتَغۡفِرۡ لَهُمۡ إِن تَسۡتَغۡفِرۡ لَهُمۡ سَبۡعِينَ مَرَّةٗ فَلَن يَغۡفِرَ ٱللَّهُ لَهُمۡۚ ذَٰلِكَ بِأَنَّهُمۡ كَفَرُواْ بِٱللَّهِ وَرَسُولِهِۦۗ وَٱللَّهُ لَا يَهۡدِي ٱلۡقَوۡمَ ٱلۡفَٰسِقِينَ
Whether you (O Muhammad ﷺ) 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 (Muhammad ﷺ). And Allah guides not those people who are Fasiqun (rebellious, disobedient to Allah).
Chapter 51, Verse 18, The winnowing winds
سورة الذاريات
وَبِٱلۡأَسۡحَارِ هُمۡ يَسۡتَغۡفِرُونَ
And in the hours before dawn, they were (found) asking (Allah) for forgiveness,
Chapter 63, Verse 6, The Hypocrites
سورة المنافقون
سَوَآءٌ عَلَيۡهِمۡ أَسۡتَغۡفَرۡتَ لَهُمۡ أَمۡ لَمۡ تَسۡتَغۡفِرۡ لَهُمۡ لَن يَغۡفِرَ ٱللَّهُ لَهُمۡۚ إِنَّ ٱللَّهَ لَا يَهۡدِي ٱلۡقَوۡمَ ٱلۡفَٰسِقِينَ
It is equal to them whether you (Muhammad ﷺ) ask forgiveness or ask not forgiveness for them. Verily, Allah guides not the people who are the Fasiqin (rebellious, disobedient to Allah).
Chapter 71, Verse 10, Nooh
سورة نوح
فَقُلۡتُ ٱسۡتَغۡفِرُواْ رَبَّكُمۡ إِنَّهُۥ كَانَ غَفَّارٗا
"I said (to them): 'Ask forgiveness from your Lord; Verily, He is Oft-Forgiving;
Chapter 4, Verse 106, The Women
سورة النساء
وَٱسۡتَغۡفِرِ ٱللَّهَۖ إِنَّ ٱللَّهَ كَانَ غَفُورٗا رَّحِيمٗا
And seek the forgiveness of Allah, certainly, Allah is Ever Oft-Forgiving, Most Merciful.