Jami` at-Tirmidhi, Book 20, Hadith 25 (In-Book) ⓘ
Narrated Ibn 'Abbas: That Sa'd bin 'Ubadah asked the Messenger of Allah about a vow that was due from his mother, who died before fulfilling it. The Prophet said: "Fulfill it for her."
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا اللَّيْثُ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ سَعْدَ بْنَ عُبَادَةَ، اسْتَفْتَى رَسُولَ اللَّهِ صلى الله عليه وسلم فِي نَذْرٍ كَانَ عَلَى أُمِّهِ تُوُفِّيَتْ قَبْلَ أَنْ تَقْضِيَهُ فَقَالَ النَّبِيُّ صلى الله عليه وسلم " اقْضِهِ عَنْهَا " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
also referenced under: Hadith 1546 (Reference) & Volume 3, Book 18, Hadith 1546 (DarusSalam)