Sahih Bukhari Volume 004, Book 051, Hadith Number 031.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 51. Wills and Testaments (Wasaayaa)
Narated By Ibn Abbas : A man said to Allah's Apostle , "My mother died, will it benefit her if I give in charity on her behalf?" The Prophet replied in the affirmative. The man said, "I have a garden and I make you a witness that I give it in charity on her behalf."