Hadith 23:38
It was narrated from Abu Hurairah that the Prophet said:
"The Muslim does not have to pay Sadaqah on his slave or his horse."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ خُثَيْمِ بْنِ عِرَاكِ بْنِ مَالِكٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " لَيْسَ عَلَى الْمُسْلِمِ صَدَقَةٌ فِي غُلاَمِهِ وَلاَ فِي فَرَسِهِ "
Original Reference: Sunan an-Nasa'i 2472