Why does Surah An-Naba say the disbelievers were punished because they 'did not expect any reckoning'?

Answer

In An-Naba 78:27, the Qur'an identifies the root cause of the disbelievers' punishment: 'Indeed, they were a people who did not expect any reckoning.' The phrase 'lā yarjūna ḥisāban' means they neither hoped for nor feared a Day of Judgment when their deeds would be brought to account. According to al-Ṭabarī, this absence of expectation removed all restraint from their conduct, so they lived as if there were no accountability. Al-Qurṭubī notes that disbelief in the reckoning is effectively disbelief in the Resurrection itself, and it is the foundation that led them to the next sin mentioned in verse 28 — denying God's signs with willful, emphatic denial. The logic of the passage is moral and causal: belief in a final reckoning is what gives weight to right and wrong, so abandoning it produces a life of heedlessness and rejection. The punishment, therefore, is not arbitrary; it answers a sustained posture of denial. Al-Saʿdī summarizes that because they did not work for that Day, they had nothing prepared for it, and so the recompense follows justly from their own choices.