Mukhtasar Bukhari

Narrated from Ummul Momineen Maimunah bint Al-Harith (may Allah be pleased with her) that she freed one of her slave girls without seeking permission from the Prophet (peace and blessings be upon him). Then, when it was her turn (the day when the Prophet would stay with her), she said, "Do you know that I have freed my slave girl?" The Prophet (peace and blessings be upon him) said, "Have you really freed her?" She replied, "Yes." The Prophet (peace and blessings be upon him) said, "If you had given her to your maternal relatives, you would have obtained more reward in that."

Umm al-Mu’minin Aisha (may Allah be pleased with her) said that whenever the Messenger of Allah (peace and blessings be upon him) intended to travel, he would draw lots among his wives. Whosever name was drawn, he would take her with him. And the Prophet (peace and blessings be upon him) would assign one day and night for each of his wives, except for Sawda bint Zam’a (may Allah be pleased with her), who gave her day and night to Umm al-Mu’minin Aisha (may Allah be pleased with her), seeking thereby the pleasure of the Messenger of Allah (peace and blessings be upon him).