ذَلِكَ بِأَنَّهُمْ قَالُوا لَن تَمَسَّنَا النَّارُ إِلَّا أَيَّامًا مَّعْدُودَاتٍ وَغَرَّهُمْ فِي دِينِهِم مَّا كَانُوا يَفْتَرُونَ
That is because they say, ‘The Fire shall not touch us except for a number of days,’ and they have been misled in their religion by what they used to fabricate.
Agha Ali Puya Commentary
Commentary on Quran 3:24
[Pooya/Ali Commentary 3:24] Aqa Mahdi Puya says: The arrogant persistence to follow their own opinion, based upon conjecture, in the application of divine laws, created a rebellious tendency in the people of the book, which encouraged them to presume that ultimate salvation is obtainable only by mere (what is said and nothing else) declaration of the faith, and if there is punishment for misdeeds and wrongdoing, it would be only for a certain number of days. As mentioned in verse 22 of this surah, there shall be no helper for them on the day of reckoning.