وَقَالُوا لَن تَمَسَّنَا النَّارُ إِلَّا أَيَّامًا مَّعْدُودَةً ۚ قُلْ أَتَّخَذْتُمْ عِندَ اللَّهِ عَهْدًا فَلَن يُخْلِفَ اللَّهُ عَهْدَهُ ۖ أَمْ تَقُولُونَ عَلَى اللَّهِ مَا لَا تَعْلَمُونَ
Wa qaaloo lan tamassanan naaru illaa ayyaamam ma'doodah; qul attakhaztum 'indal laahi 'ahdan falan yukhlif allaahu 'ahdahoo am taqooloona 'alal laahi maa laa ta'lamoon
And they say, "The fire will only touch us for a number of days." Say, "Have you taken a covenant with God? For God will never break his covenant. Or are you saying about God what you do not know?"
The claim being answered sets a limit in advance, a fixed number of days, and the reply asks only for its warrant. Ayyāman maʿdūdah, the phrase carrying it, returns almost word for word later in this same surah for the days of fasting, where it reads maʿdūdāt and a counted term is exactly the mercy intended. What the answer refuses is the arithmetic, not the hope, and it leaves the question standing as a question.