يَوْمَ يُنفَخُ فِى ٱلصُّورِ فَتَأْتُونَ أَفْوَاجًا
Sentence structure
This يَوْمَ explains the Day mentioned in the preceding ayah. The passive clause يُنفَخُ فِى ٱلصُّورِ is attached to it, and فَتَأْتُونَ أَفْوَاجًا states the resulting gathering in crowds.
يَوْمَ — the Day when
Grammar: An accusative adverb of time and مضاف. It is an apposition explaining يَوْمَ ٱلْفَصْلِ in the preceding ayah.
يُنفَخُ — it will be blown
Grammar: A third-person masculine singular imperfect passive verb. The prepositional phrase فِى ٱلصُّورِ fills the passive-subject relation.
فِى — in
Grammar: A preposition linked to يُنفَخُ.
ٱلصُّورِ — the Trumpet
Grammar: A definite masculine noun made genitive by فِى. The prepositional phrase completes the passive clause.
فَتَأْتُونَ — then you will come
Grammar: فَـ marks sequence. تَأْتُونَ is a second-person masculine plural imperfect verb and one of the five verbs. “و” is wāw al-jamāʿah: an attached subject pronoun. The final “نَ” is the indicative nūn; its retention marks the verb as indicative.
أَفْوَاجًۭا — in crowds
Grammar: An indefinite accusative plural noun functioning as حال, describing how you will come. فَوْج is its singular.