The Messenger of Allah ﷺ said, "I have exempted you from paying zakat on horses and slaves, but bring forth a quarter of the tenth, one dirham for every forty dirhams."
حدثنا علي بن محمد حدثنا وكيع عن سفيان عن أبي إسحق عن الحارث
قال رسول الله ﷺ إني قد عفوت لكم عن صدقة الخيل والرقيق ولكن هاتوا ربع العشر من كل أربعين درهما درهما
[Its chain of transmission is daif] see hadith no. 95 for its defect. It was also related by Abu Dawud in the chapter on Zakat, in the section on the zakat of grazing livestock, hadith no. 1574, and others, from the hadith of Abu Ishaq, from Asim bin Damra, from Ali, may Allah be pleased with him, with similar wording. Bukhari, Ibn Khuzayma, and others graded it sahih.Abu Ishaq narrated using "an" (indicating a possible break in transmission), as noted previously at hadith no. 46. The hadith has corroborating narrations.