فَدَخَلْتُهَا خَاوِيَ الْوِفَاضِ
So I entered the city with my provision-bag empty.
In فدخلتها, the pronoun ها refers back to Ṣanʿāʾ. خاوي means empty; الوفاض denotes a bag or container used to carry provisions.
خاوي الوفاض gives a tangible image. The city lies before him, but the traveller lacks supplies. Hunger now becomes central to the story.