The Messenger of Allah ﷺ appointed a man from the tribe of Makhzum to collect zakat, and Abu Rafi wanted to accompany him. The Messenger of Allah ﷺ said, "Zakat is not lawful for us, and the freed slave of a people is considered one of them."
أخبرنا عمرو بن علي قال حدثنا يحيى قال حدثنا شعبة قال حدثنا الحكم
أن رسول الله ﷺ استعمل رجلا من بني مخزوم على الصدقة فأراد أبو رافع أن يتبعه فقال رسول الله ﷺ إن الصدقة لا تحل لنا وإن مولى القوم منهم
[Sahih] Reported by Abu Dawud, Zakat, chapter on charity given to Banu Hashim, no. 1650, and Tirmidhi, Zakat, chapter on the dislike of charity for the Prophet ﷺ and his household and his freedmen, no. 657, from the hadith of Shubah with this wording. Tirmidhi said, hasan sahih, and Ibn Khuzayma graded it sahih, no. 2344, as did Ibn Hibban, (Al-Ihsan), no. 3282. The hadith is also in Al-Kubra, no. 2394, and it has corroborating narrations in Bukhari, 12/48 with Al-Fath, and Muslim, no. 1069, and others.