You are reading a tafsir for the group of verses 7:48 to 7:49
مَآ أَغْنَى عَنكُمْ جَمْعُكُمْ
("Of what benefit to you was your gathering...") meaning, your great numbers,
وَمَا كُنتُمْ تَسْتَكْبِرُونَ
("...and your arrogance") This Ayah means, your great numbers and wealth did not save you from Allah's torment. Rather, you are dwelling in His torment and punishment. `Ali bin Abi Talhah reported from Ibn `Abbas,
أَهَـؤُلاءِ الَّذِينَ أَقْسَمْتُمْ لاَ يَنَالُهُمُ اللَّهُ بِرَحْمَةٍ
(Are they those, of whom you swore that Allah would never show them mercy) refers to the people of Al-A`raf who will be told when Allah decrees:
ادْخُلُواْ الْجَنَّةَ لاَ خَوْفٌ عَلَيْكُمْ وَلاَ أَنتُمْ تَحْزَنُونَ
((Behold! It has been said to them): "Enter Paradise, no fear shall be on you, nor shall you grieve.")