Musnad Ahmad 1017:22

Ishaq ibn Yusuf narrated to us, from Abd al-Malik ibn Abi Sulayman, from Abdullah ibn Ata al-Makki, from Sulayman ibn Buraydah, from his father, that a woman came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, I gave a slave girl as charity to my mother, then she died, and she (the slave girl) has returned to me in the inheritance." He said: "Allah has rewarded you, and she has returned to you in the inheritance." She said: "My mother died without having performed Hajj; will it suffice if I perform Hajj on her behalf?" He said: "Yes." She said: "My mother owed a month of fasting; will it suffice if I fast on her behalf?" He said: "Yes."