The religious learned men should not differ Sahih al-Bukhari 7330
Arabic hadith text
حَدَّثَنَا عَمْرُو بْنُ زُرَارَةَ، حَدَّثَنَا الْقَاسِمُ بْنُ مَالِكٍ، عَنِ الْجُعَيْدِ، سَمِعْتُ السَّائِبَ بْنَ يَزِيدَ، يَقُولُ كَانَالصَّاعُ عَلَى عَهْدِ النَّبِيِّ صلى الله عليه وسلم مُدًّا وَثُلُثًا بِمُدِّكُمُ الْيَوْمَ، وَقَدْ زِيدَ فِيهِ.
سَمِعَ الْقَاسِمُ بْنُ مَالِكٍ الْجُعَيْدَ
Translation
Narrated As-Sa'ib bin Yazid
The Sa' (a kind of measure) during the lifetime of the Prophet (ﷺ) used to be equal to the one Mudd (another kind of measure) and one third of a Mudd which we use today, but the Sa' of today has become large.