Mishkat al-Masabih 466

Umm Salama said that a woman told her she had a long skirt and walked in filthy places, so she told her that God’s messenger had said, "What comes after it cleanses it." Malik, Ahmad, Tirmidhi, Abu Dawud and Darimi transmitted it, the last two mentioning that the woman was an umm walad* belonging to Ibrahim b. ‘Abd ar-Rahman b. ‘Auf. *Lit. "mother of a boy". Used of a slavewoman who has borne a child to her master, and therefore gains her freedom when he dies.