Musannaf Ibn Abi Shayba 13:1040

Abu Bakr narrated to us, he said: Abdullah bin Numayr narrated to us, from Abdullah bin Ata, from Ibn Buraydah, from his father, who said: A woman came to the Prophet, may Allah bless him and grant him peace, and said: "I gave a slave girl as charity to my mother, then my mother died, and the slave girl remains." He said to her: "Your reward has become incumbent, and she has returned to you through inheritance."