7. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Barqiy from ibn Sinan from ’Isma‘il ibn Jabir who has said the following: “I asked abu ‘Abd Allah عليه السلام, about the water which does not become unclean by anything. He (the Imam) replied, ‘It is one Kur.’ I then asked, ‘How much is one Kur?’ He (the Imam) replied, ‘It is three shibr by three shibr in size.’”