(9) باب ذِكْرِ الاِخْتِلاَفِ عَلَى سُفْيَانَ
It was narrated that Ibn 'Abbas said:
"Sa'd bin 'Ubadah Al-Ansari consulted the Messenger of Allah about an (outstanding) vow that his mother had to fulfill, but she died before doing so. The Messenger of Allah said: 'Fulfill it on her behalf.'"
Reference: Sunan an-Nasa'i 3662
In-book reference: Book 30, Hadith 52
English translation: Vol. 4, Book 30, Hadith 3692