What the sa is

Ibn Abi Layla said: We measured the sa' of Madinah and found that it exceeded the Hajjaji sa' (the sa' of al-Hajjaj bin Yusuf) in measure.

Musa bin Talhah said: The Hajjaji sa' is the sa' of Sayyiduna Umar bin al-Khattab (may Allah be pleased with him).

It is narrated from Ibrahim that the Hajjaji qafiz is the sa'.

Mughirah said: In the matters on which Ibrahim gave fatwas, whether the expiation for an oath, or purchasing, or feeding sixty poor people, and in what he said the tithe or half-tithe was due on, he used to give his fatwa by the Hajjaji qafiz, and he said: It is the sa'.

Yahya bin Adam said: I heard Hasan say: The sa' of Sayyiduna Umar (may Allah be pleased with him) was eight ratls. And Sharik said: More than seven ratls and less than eight.