Al-Walid said :

I asked Abu `Amr: What are they writing? He said: The sermon which he heard that day.

حَدَّثَنَا عَلِيُّ بْنُ سَهْلٍ الرَّمْلِيُّ، قَالَ حَدَّثَنَا الْوَلِيدُ، قَالَ قُلْتُ لأَبِي عَمْرٍو مَا يَكْتُبُوهُ قَالَ الْخُطْبَةَ الَّتِي سَمِعَهَا يَوْمَئِذٍ مِنْهُ ‏.‏