Sahih al-Bukhari 6712

Arabic

حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا الْقَاسِمُ بْنُ مَالِكٍ الْمُزَنِيُّ، حَدَّثَنَا الْجُعَيْدُ بْنُ عَبْدِ الرَّحْمَنِ، عَنِ السَّائِبِ بْنِ يَزِيدَ، قَالَ كَانَ الصَّاعُ عَلَى عَهْدِ النَّبِيِّ صلى الله عليه وسلم مُدًّا وَثُلُثًا بِمُدِّكُمُ الْيَوْمَ فَزِيدَ فِيهِ فِي زَمَنِ عُمَرَ بْنِ عَبْدِ الْعَزِيزِ‏.‏

English translation

Narrated Al-Ju'aid bin `Abdur-Rahman:As-Sa'ib bin Yazid said, "The Sa' at the time of the Prophet (ﷺ) was equal to one Mudd plus one-third of a Mudd of your time, and then it was increased in the time of Caliph `Umar bin `Abdul `Aziz

Reference: Sahih al-Bukhari 6712, Book of Expiation for Unfulfilled Oaths. English translation by Dr. Muhammad Muhsin Khan.