وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرِ بْنِ عَمْرِو بْنِ حَزْمٍ، أَنَّهُ قَالَ جَاءَ كِتَابٌ مِنْ عُمَرَ بْنِ عَبْدِ الْعَزِيزِ إِلَى أَبِي وَهُوَ بِمِنًى أَنْ لاَ يَأْخُذَ مِنَ الْعَسَلِ وَلاَ مِنَ الْخَيْلِ صَدَقَةً ‏.‏

Yahya related to me from Malik that Abdullah ibn Abi Bakr ibn Amribn Hazim said, "A message came from Umar ibn Abd al-Aziz to my fatherwhen he was in Mina telling him not to take zakat from either honey orhorses." Translation Not Available

Book reference: Muwatta Imam Malik Book 17 Hadith 616
Web reference: Muwatta Imam Malik Book 17 Hadith 40