What accurately contrasts the opening and final uses of aḥad in al-Ikhlāṣ?

Supplementary Practice 23: Comparative Rhetorical Study of Sūrat al-Masad and al-Ikhlāṣ

• Exactly the same syntax and finite verb in both places
• Denial of begetting first and wealth last
• Positive oneness at the opening; denial of any equal at the end
• A vocative in both positions