«مِثْلَ هِلَالِ الْأُفْقِ حِينَ افْتَرَّا»
Like the crescent at the horizon when it first shines forth.
Hilāl denotes a slender crescent; ufuq is the horizon. Iftarra evokes appearing or gleaming.
This comparison links back to the traveller's bent frame and pallor. His body is viewed through the recognizable curved shape of a thin crescent, mixing visual beauty with distress.