It is narrated from Sayyiduna Abu Shurayd bin Suwayd Thaqafi (may Allah be pleased with him) that his mother had made a will that he should free a Muslim slave on her behalf. So he asked the Messenger of Allah (peace and blessings be upon him) that he had a black Sudanese slave woman; could he free her? The Messenger of Allah (peace and blessings be upon him) said: "Bring her to me." So I called her and she came. The Messenger of Allah (peace and blessings be upon him) said to her: "Who is your Lord?" She said: "Allah, the Exalted." He (peace and blessings be upon him) then said: "Who am I?" She said: "You are the Messenger of Allah." Upon hearing this, the Messenger of Allah (peace and blessings be upon him) said: "Set her free, for she is a believer."