In this hadith, the Mother of the Believers ‘A’ishah (may Allah be pleased with her) describes how the Prophet (blessings and peace of Allah be upon him) did ghusl. What is meant by ghusl is that which removes the janabah (state of impurity) that results from emitting maniy (semen) or having intercourse. The Prophet (blessings and peace of Allah be upon him) did ghusl with an amount of water that would fill a vessel that holds a sa‘. The sa‘ is a unit of measurement equivalent to four mudds or eight ratls. There is a difference of opinion regarding the equivalent to the ratl in terms of modern units of measurement. It is said that the ratl is equivalent to approximately 380 grams, or less than half a litre; or it is said that it is equivalent to 538 grams, or more than half a litre. Then Abu Salamah ibn ‘Abdul Rahman ibn ‘Awf said that ‘A’ishah (may Allah be pleased with her) explained to him and her brother, ‘Abdul Rahman ibn Abi Bakr al-Siddiq – or it was said that it was ‘Abdullah ibn Yazid, her foster-brother – in practical terms how the Prophet (blessings and peace of Allah be upon him) did ghusl with this amount of water. She called for a vessel the size of a sa‘, and did ghusl from it. There was a screen between her and them, hence they did not see anything but the pouring of water on her head. Abu Salamah was the son of ‘A’ishah’s foster sister; he had been breast-fed by Umm Kalthum, the daughter of Abu Bakr. So the two men present were her mahrams. Hence they saw nothing of her ghusl except the pouring of water onto her head, for that is what is permissible for a man to see of the woman who is his mahram. Were it not that they saw that, there would have been no point in calling for water to be brought and purifying herself in their presence, because if she did all of that behind a screen, where they could not see her at all, it would have been sufficient for her to teach them in words only. She only put the screen to cover the lower part of her body, and what it is not permissible for a mahram to look at..