Bukhari Collection: ::Book Number 4:: Hadith # 19
Narrated Ibn `Abbas:The mother of Sa`d bin 'Ubada died in his absence. He said, "O Allah's Apostle! My mother died in my absence; will it be of any benefit for her if I give Sadaqa on her behalf?" The Prophet said, "Yes," Sa`d said, "I make you a witness that I gave my garden called Al Makhraf in charity on her behalf."