حَدَّثَ الْحَارِثُ بْنُ هَمَّامٍ قَالَ
Al-Ḥārith ibn Hammām related the account and said.
This is a narrative framing formula. The story is introduced through a named narrator, rather than through an unmediated authorial voice. First-person verbs then convey his experience: he journeyed, entered the city, and lacked provisions.
Al-Ḥārith ibn Hammām is the storyteller in this opening. We should not confuse him with characters introduced later.