What follows from the brevity of fa-āwā, fa-hadā and fa-aghnā?

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

• Each necessarily omits an entire oath response
• All are negative imperfect verbs
• All hide quotations from unrelated poetry
• The clauses are concise, but the same ellipsis need not be posited in each