ذَٰلِكَ بِأَنَّهُمْ قَالُوا لَن تَمَسَّنَا ٱلنَّارُ إِلَّآ أَيَّامًا مَّعْدُودَٰتٍ ۖ وَغَرَّهُمْ فِى دِينِهِم مَّا كَانُوا يَفْتَرُونَ

Thalika bi-annahum qaloo lantamassana annaru illa ayyamanmaAAdoodatin wagharrahum fee deenihim ma kanooyaftaroon

That is because they say, "Never will the Fire touch us except for [a few] numbered days," and [because] they were deluded in their religion by what they were inventing.