Why is al-Jawn repeated with “of the clan of Banū al-Aws”?

al-Ḥārith ibn Ḥillizah: Ḥujr, Royal Kinship and the Dhū al-Majāz Covenant (verses 56–67)

• To count two horses
• To state dates of two wars
• To change a noun into a verb
• To specify the intended al-Jawn