What is the ruling on freeing a female slave whom one mistook for a stranger?
Chapter on Explicit Divorce and Others
Al-Mughni
Book of Divorce
Primary text
If a man encounters his female slave, mistakes her for a non-mahram woman (Ajnabyyah), and says to her, 'You are free' (Anti Hurrah), or 'Move aside, O free woman' (Tanahhay ya Hurrah), no manumission occurs. This is because the utterance lacked the necessary intent, treating it as an accidental slip of the tongue.
Supporting text
It is probable that the slave is not freed because the common custom allows people to address unfamiliar individuals as 'O free woman' (Ya Hurrah), diminishing the indication of specific intent regarding manumission.