It is narrated from Hazrat Umm Salamah (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said: When any of you women has a slave who is a mukatab (one who has a contract of manumission) and he possesses enough to pay the amount of his contract and thereby gain his freedom by handing it over to his owner, then that woman should observe veil from her slave.