What is the "Day of Decision" (Yawm al-Fasl) in Surah An-Naba 78:17?

Answer

In Surah An-Naba 78:17, "the Day of Decision" (Yawm al-Faṣl) is one of the Qur'an's names for the Day of Judgment. The Arabic word faṣl means to separate, distinguish, or decide definitively—so it is the Day on which Allah passes final judgment between all of creation, separating truth from falsehood and the people of Paradise from the people of the Fire, settling every dispute that divided them in worldly life. The classical commentators al-Ṭabarī, Ibn Kathīr, al-Qurṭubī, and al-Saʿdī agree on this meaning. The verse adds that this Day "kāna mīqātan"—it is an appointed time: a fixed, predetermined meeting-time and term, neither hastened nor delayed, known to Allah alone. The word mīqāt (from the same root as waqt, time) signals that the Day is not a vague possibility but a scheduled certainty. The surrounding verses (78:18-20) then sketch its onset: the trumpet sounds, people rise from their graves in crowds, the sky tears open, and the mountains are set moving until they vanish like a mirage. The passage is among several in the Qur'an that name the Resurrection by its function—decision and separation—rather than only by its timing.