(Allah hath (now) revealed the fairest of statements…) [39:23].
‘Abd al-Qahir ibn Tahir al-Baghdadi informed us> Abu ‘Amr ibn Matar> Ja‘far ibn Muhammad al-Firyabi> Ishaq ibn Rahwayh> ‘Amr ibn Muhammad al-Qurashi> Khallad al-Saffar> ‘Amr ibn Qays al-Mula’i> ‘Amr ibn Murrah> Mus‘ab ibn Sa‘d [ibn Abi Waqqas] who said: “They said: ‘O Messenger of Allah, why do you not relate to us statements’, and so Allah, exalted is He, revealed (Allah hath (now) revealed the fairest of statements…)”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou