Sunan Ibn Majah, Hadith 2112 ⓘ
It was narrated that Ibn Abbas said: "The Messenger of Allah offered expiation of a Sa' of dates, and he enjoined the people to do likewise. Whoever does not have that (must give) half a Sa' of wheat."
حَدَّثَنَا الْعَبَّاسُ بْنُ يَزِيدَ، حَدَّثَنَا زِيَادُ بْنُ عَبْدِ اللَّهِ الْبَكَّائِيُّ، حَدَّثَنَا عُمَرُ بْنُ عَبْدِ اللَّهِ بْنِ يَعْلَى الثَّقَفِيُّ، عَنِ الْمِنْهَالِ بْنِ عَمْرٍو، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَفَّرَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ بِصَاعٍ مِنْ تَمْرٍ وَأَمَرَ النَّاسَ بِذَلِكَ فَمَنْ لَمْ يَجِدْ فَنِصْفُ صَاعٍ مِنْ بُرٍّ .
also referenced under: Book 11, Hadith 2190 (In-Book) & Volume 3, Book 11, Hadith 2112 (DarusSalam)