I heard Ash-Shuʿbi saying, "I was told by a man who had passed with the Prophet ﷺ by a grave that was separate from the other graves that he (the Prophet ﷺ ) led them in the prayer and they prayed behind him." I said, "O Abu ʿAmr! Who narrated that to you?" He replied, "Ibn ʿAbbas."
أَخْبَرَنِي مَنْ مَرَّ مَعَ النَّبِيِّ ﷺ عَلَى قَبْرٍ مَنْبُوذٍ فَأَمَّهُمْ وَصَلَّوْا خَلْفَهُ قُلْتُ مَنْ حَدَّثَكَ هَذَا يَا أَبَا عَمْرٍو قَالَ ابْنُ عَبَّاسٍ ؓ