(16) باب مَا ذَكَرَ النَّبِيُّ صلى الله عليه وسلم وَحَضَّ عَلَى اتِّفَاقِ أَهْلِ الْعِلْمِ
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.
Reference: Sahih al-Bukhari 7330
In-book reference: Book 96, Hadith 59
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 92, Hadith 430