عَنْ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: فَرَضَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ هَذِهِ الصَّدَقَةَ كَذَا وَكَذَا وَنِصْفَ صَاعٍ بُرًّا
It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) prescribed one sa’ each of such-and-such items and half a sa’ of wheat for Sadaqat al-Fitr.