What is the authenticity of the Hadith of Umm Salamah to the Messenger of Allah, peace and blessings be upon him, regarding a woman letting down her garment "a handspan" and then "a cubit, no more than that"? And what is the measure of a handspan and a cubit, and from where does their calculation begin? Is this measure binding for prayer and when leaving the house, or only for prayer? Is it necessary to wear socks inside the house for prayer?

The mentioned Hadith (definition) is authentic. The measure of a shibr (span) is the distance between the tip of the middle finger and the thumb, which is half a cubit, estimated at approximately half a meter. The beginning of the shibr starts from its heel, according to the Hadith of Anas ibn Malik regarding the Prophet's (peace be upon him) spanning for Fatimah. Covering the feet is necessary in prayer and when leaving the house. Limiting the covering of the feet to specific socks is disliked (makruh (definition)).