ذٰلِكَ بِاَنَّهُمْ قَالُوْا لَنْ تَمَسَّنَا النَّارُ اِلَّآ اَيَّامًا مَّعْدُوْدٰتٍ ۖ وَّغَرَّهُمْ فِيْ دِيْنِهِمْ مَّا كَانُوْا يَفْتَرُوْنَ ( آل عمران: ٢٤ )
Zaalika bi annahum qaaloo lan tamassanan naaru illaaa ayyaamam ma'doodaatinw wa gharrahum fee deenihim maa kaanoo yaftaroon (ʾĀl ʿImrān 3:24)
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. (Ali 'Imran  : 24)
1 Mufti Taqi Usmani
That is because they have said: “The Fire shall not touch us except for a few days.” Thus they are deceived in their faith by what they themselves used to invent.