(a) Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) and I used to bathe from a single vessel, and that (vessel) was a faraq. (b) Imam al-Zuhri (may Allah have mercy on him) said that its measure is five qists. (c) Abu Amr said that a qist is four ratl. (d) Ibn Uyaynah (may Allah have mercy on him) said: A faraq held three sa' of water. (e) Imam Ahmad bin Hanbal (may Allah have mercy on him) said that a faraq was sixteen ratl. And he said: The sa' of Ibn Abi Dhi'b is five and one third ratl. As for the one who said eight ratl, his report is not preserved. (f) Imam al-Shafi'i (may Allah have mercy on him) said: It has reached us that the Prophet (peace and blessings be upon him) performed ablution with one mudd and bathed with one sa'.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 928