«وَأَقْبَلَتْ يَوْمَ جَدَّ الْبَيْنُ فِي حُلَلٍ سُودٍ»
When separation became pressing, she approached wearing black garments.
Bayn means separation, and ḥulal is the plural of ḥullah, a garment or outfit. Jadda al-bayn suggests that the moment of parting has become serious and immediate.
Black clothing externalizes her grief. The verse presents emotion through a visible, culturally intelligible detail: the garments make sorrow recognizable before the speaker names it directly.