Repeated wa-naḥnu binds several lines into a collective declaration. Al-ḥābisūn, al-ḥākimūn, al-ʿāzimūn, al-tārikūn, al-ākhidhūn are plural active participles that present enduring traits.
Unlike the singular 'I', the repeated 'we' makes the tribe itself the speaking subject. It gives the boasting rhetorical force without turning each claim into an independently established historical fact.