Sunan Abi Dawud 1611
سنن أبي داود#1611SahihIbn ‘Umar said :The Messenger of Allah(ﷺ) prescribed as zakat payable by slave and freeman, male and female, among the muslims on closing the fast of Ramadan one sa of dried dates or one sa’ of barley. (This tradition was read out byu ‘Abd Allah b. Maslamah to Malik)
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 (1504) Sahih Muslim (984)
In-book reference: 9:56