«غَشِيَتْنِي نَدَامَةُ الْفَرَزْدَقِ ... وَالْكُسَعِيِّ لَمَّا اسْتَبَانَ النَّهَارُ»
I was overcome by regret like that of al-Farazdaq, and of al-Kusaʿī when day revealed the truth.
Al-Farazdaq is remembered here for regretting divorce from his wife al-Nawwār. In the tale of al-Kusaʿī, an archer breaks his bow under a mistaken belief, only to discover his success in daylight.
Al-Ḥārith regrets missing a chance to reveal Abū Zayd’s identity in a way that might have brought him further aid. The ending turns on lost opportunity, not denial of the original gift.