Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: The Messenger of Allah (peace and blessings be upon him) ordered Sadaqat al-Fitr (the charity of breaking the fast) upon every Muslim, free or slave, young or old: one sa' of dates or one sa' of barley.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13340