«فَإِنْ كُنْتَ صَدَعْتَ عَنْ وَصْفِكَ بِالْيَقِينِ فَأْتِ بِآيَةٍ إِنْ كُنْتَ مِنَ الصَّادِقِينَ»[
If your description was spoken with certainty, produce a clear proof of its truth.
Ṣadaʿta involves open declaration, while āyah here functions as a sign or proof. The phrasing echoes a recognizable Quranic challenge, but its purpose in the story is literary: provide an actual example that meets the demanding constraint.
The criteria have finally become specific. The elder cannot prevail simply by speaking confidently; the work itself must display the disputed command of language.