هَلْ نَحْنُ لِابْنِ هِنْدٍ رِعَاءُ
Are we herdsmen serving Ibn Hind?
Hal is interrogative, naḥnu the subject of the nominal clause, riʿāʾ its predicate, and li-bni Hind indicates the relationship being challenged. The poet does not expect neutral information.
The interrogative form performs rhetorical denial: to frame the tribe as mere herdsmen would be degrading, and the question rejects that claim.