Wills and Testaments (Wasaayaa) 
Bukhari :: Book 4 :: Volume 51 :: Hadith 23
Narrated Ibn 'Abbas:
Sad bin Ubada consulted Allah's Apostle saying, "My mother died and she had an unfulfilled vow." The Prophet said, "Fulfill it on her behalf."
Wills and Testaments (Wasaayaa)
Bukhari :: Book 4 :: Volume 51 :: Hadith 23
Narrated Ibn 'Abbas:
Sad bin Ubada consulted Allah's Apostle saying, "My mother died and she had an unfulfilled vow." The Prophet said, "Fulfill it on her behalf."