Narrated Ibn 'Abbas:
Sa'd b. 'Ubadah asked the Messenger of Allah ﷺ: My Mother has died and she could not fulfill her vow which she had taken. The Messenger of Allah ﷺ said: Fulfill it on her behalf.

حَدَّثَنَا الْقَعْنَبِيُّ، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، : أَنَّ سَعْدَ بْنَ عُبَادَةَ، اسْتَفْتَى رَسُولَ اللَّهِ ﷺ فَقَالَ : إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا نَذْرٌ لَمْ تَقْضِهِ . فَقَالَ رَسُولُ اللَّهِ ﷺ " اقْضِهِ عَنْهَا " .