وَأَنَّ ٱلَّذِينَ لَا يُؤْمِنُونَ بِٱلْـَٔاخِرَةِ أَعْتَدْنَا لَهُمْ عَذَابًا أَلِيمًا
Wa annal lazeena laa yu'minoona bil aakhirati a'tadnaa lahum 'azaaban aleemaa
warns that We have prepared an agonizing punishment for those who do not believe in the world to come.
And for those who do not believe in the hereafter, we have prepared a painful punishment.
This clause is grammatically bound to the one before it: both hang on anna, so the warning arrives inside the same sentence that announces good news. Grammarians noticed the strain and split over which verb governs the second anna — the announcing, which would make a threat part of the good news, or the earlier statement about what the Qur'an guides to. The English has to break the sentence in two; the Arabic does not.