The Book of Zakah
23/44. Chapter:
How Much Is A Sa'?
Sunan an-Nasai
أَخْبَرَنَا عَمْرُو بْنُ زُرَارَةَ، قَالَ أَنْبَأَنَا الْقَاسِمُ، - وَهُوَ ابْنُ مَالِكٍ - عَنِ الْجُعَيْدِ، سَمِعْتُ السَّائِبَ بْنَ يَزِيدَ، قَالَ كَانَ الصَّاعُ عَلَى عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم مُدًّا وَثُلُثًا بِمُدِّكُمُ الْيَوْمَ وَقَدْ زِيدَ فِيهِ . قَالَ أَبُو عَبْدِ الرَّحْمَنِ وَحَدَّثَنِيهِ زِيَادُ بْنُ أَيُّوبَ .
It was narrated from Al-Ju'aid: "I heard As-Sa'ib bin Yazid say: 'During the time of Allah's messenger, the Sa' was equal to a Mudd and third of the Mudd you use today, and the Sa' of today has become large."' (Sahih) Abu 'Abdur-Rahman (An-Nasa'i) said: And Ziyad bin Ayyub narrated it to me.
Reference : Sunan an-Nasa'i 2519In-book reference : Book 23, Hadith 85English translation : Vol. 3, Book 23, Hadith 2521