Surah An-Naba 78:18

يَوْمَ يُنفَخُ فِى ٱلصُّورِ فَتَأْتُونَ أَفْوَاجًا

The Day the Horn is blown and you will come forth in multitudes

Translation: Saheeh International

Tafsir

the day the Trumpet the Horn is blown yawma yunfakhu fī’l-sūri is either a substitution for or an explication of yawma’l-fasli ‘the Day of Decision’ the blower being Isrāfīl and you come forth from your graves to the site of the Resurrection in droves in diverse groups

Excerpt from Tafsir al-Jalalayn, commentary on 78:18, via Quran.com. The reader has the full commentary and 9 more tafsirs.