Sahih Muslim
The Book of Zakat (Kitab Al-Zakat)
Book Number: 005 / Hadith Number: 2153
Ibn Umar reported that the Messenger of Allah (may peace be upon him) prescribed Zakat-ul-Fitr of Ramadan one sa' of dates or one sa' of barley for every individual among the Muslims (whether) free man or slave, male or female, young or old.