Regarding The Imam Taking Something From The Fa'i For Himself

Narrated Amr ibn Abasah:

The Messenger of Allah ﷺ led us in prayer facing a camel which had been taken in booty, and when he had given the salutation, he took a hair from the camel's side and said: I have no right as much as this of your booty, but only to the fifth. and the fifth is returned to you.

حَدَّثَنَا الْوَلِيدُ بْنُ عُتْبَةَ، حَدَّثَنَا الْوَلِيدُ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْعَلاَءِ، أَنَّهُ سَمِعَ أَبَا سَلاَّمٍ الأَسْوَدَ، قَالَ سَمِعْتُ عَمْرَو بْنَ عَبَسَةَ، قَالَ صَلَّى بِنَا رَسُولُ اللَّهِ ﷺ إِلَى بَعِيرٍ مِنَ الْمَغْنَمِ فَلَمَّا سَلَّمَ أَخَذَ وَبَرَةً مِنْ جَنْبِ الْبَعِيرِ ثُمَّ قَالَ " وَلاَ يَحِلُّ لِي مِنْ غَنَائِمِكُمْ مِثْلُ هَذَا إِلاَّ الْخُمُسَ وَالْخُمُسُ مَرْدُودٌ فِيكُمْ " .