What is a sound observation about the missing opening fā in the repeated verse?

Supplementary Practice 18: Rhetorical Analysis of Sūrat al-Ḍuḥā and Sūrat al-Sharḥ

• The first fā links back; the second independently restates the assurance
• The second negates the first
• Inna becomes meaningless without fā
• The second necessarily becomes an interrogative