The Messenger of Allah ﷺ said, "There is no zakat due on a Muslim's slave or on his horse."
حدثنا محمد بن جعفر قال حدثنا شعبة عن عبد الله بن دينار قال سمعت سليمان بن يسار يحدث عن عراك بن مالك
عن رسول الله ﷺ قال ليس على غلام المسلم ولا على فرسه صدقة
Its isnad is sahih. Bukhari narrated the hadith with similar wording (2/149) in the chapter on the obligation of zakat, "There is no charity due on a Muslim for his horse," and Muslim (2/676, no. 982) in the Book of Zakat, "There is no zakat due on a Muslim for his slave," and Nasai (5/35-36, nos. 2467, 2472), and Abdul-Razzaq (4/33, no. 6878).