Explanation of the hadith
When Barīrah, one of ‘Ā’ishah’s slave girls, was freed from slavery she was married to Mughīth, who was also a slave. So she had the choice of continuing her marriage to him or annulling it, and she choose to end her marriage. The Hadīth states that she observed an ‘Iddah of three menstrual cycles, even though her marriage ended through annulment and not through divorce, and that this annulment occurred during the life of her husband, who remained a slave, and not after his death.