كتاب الزكاة
Read the English translation first, with the original Arabic directly underneath.
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.
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 .