إِنْ كُنْتِ أَزْمَعْتِ الْفِرَاقَ فَإِنَّمَا زُمَّتْ رِكَابُكُمْ بِلَيْلٍ مُظْلِمِ
If you have firmly resolved to part, your riding animals were already made ready in the dark of night.
Azmaʿti denotes a firm resolve. Zummat rikābukum presents the riding animals made ready for departure; the verb is passive.
Bi-laylin muẓlim adds secrecy and emotional abruptness. The poet’s statement is both a reproach and a reconstruction of the moment when the caravan left.