«فَشَكَرَ عِنْدَ ذَلِكَ الصُّنْعَ وَاسْتَنْفَدَ فِي الثَّنَاءِ الْوُسْعَ»
He thanked them for the kindness and exhausted his capacity in praise.
Al-ṣunʿ here is the generous deed, al-thanāʾ is commendation, and al-wusʿ is the full extent of one’s ability. Istanfada means to use something up.
Abū Zayd’s extraordinary command of language comes forward again. A speaker who first sought help now directs his eloquence toward gratitude and praise, maintaining his hold on the gathering.