Sunan Abi Dawud 1595
سنن أبي داود#1595SahihNarrated Abu Hurairah :The Messenger of Allah(ﷺ) as saying No sadaqah is due from a Muslim on his slave or his horse
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (1463) Sahih Muslim (982)
In-book reference: 9:40