Sunan Ibn Mājah 2132✓ 5Sahih
حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَنْبَأَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ سَعْدَ بْنَ عُبَادَةَ، اسْتَفْتَى رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ فِي نَذْرٍ كَانَ عَلَى أُمِّهِ تُوُفِّيَتْ وَلَمْ تَقْضِهِ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " اقْضِهِ عَنْهَا " .
It was narrated from Ibn 'Abbas' that :Sa'd bin 'Ubadah asked the Messenger of Allah (ﷺ) about a vow which his mother had made, but she had died without fulfilling it. The Messenger of Allah (ﷺ) said: "Fulfill it on her behalf