What does "the trumpet is sounded" mean in Surah An-Naba 78:18?

Answer

"On the Day the trumpet is sounded" (yawma yunfakhu fī al-ṣūr) in Surah An-Naba 78:18 refers to the blast on the Trumpet (al-ṣūr) that signals the Resurrection. In Islamic teaching the ṣūr is a horn that the angel charged with it will blow by Allah's command. The Qur'an describes more than one blast: one at which those in the heavens and earth fall down (or are stunned), and another at which they rise and stand looking on (Surah az-Zumar 39:68). The verse here points to the blast of rising, because it is immediately followed by "and you come forth in throngs" (fa-taʾtūna afwājan)—people emerging from their graves in successive crowds toward the place of gathering. The commentators explain afwājan as groups coming one after another; some relate that each community comes with its prophet, others that people are mustered in companies according to their deeds. The trumpet is thus the threshold event between worldly death and the standing for judgment. It marks the Day of Decision (78:17) actually beginning, after which the cosmic upheaval of the sky opening (78:19) and the mountains vanishing (78:20) unfolds.