«فَأَسْرَيْنَا إِلَى أَنْ نَضَا اللَّيْلُ شَبَابَهُ»
We travelled by night until the night shed its youthful darkness.
Asraynā denotes travelling at night; naḍā is associated with taking off a garment or covering. Night's shedding points toward the coming of dawn.
The personification develops rather than merely repeats: night had been described as young and dark-clad, and now it removes its covering. The passage of time becomes a character's action.