Sunan Ibn Majah, Book 11, Hadith 2215 (In-Book) ⓘ
It was narrated from Jabir bin 'Abdullsh that : a woman came to the Messenger of Allah and said: "My mother has died, and she had made a vow to fast, but she died before she could fulfill it. The Messenger of Allah said: 'Let her guardian fast on her behalf."
حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى، حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا ابْنُ لَهِيعَةَ، عَنْ عَمْرِو بْنِ دِينَارٍ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ، . أَنَّ امْرَأَةً، أَتَتْ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ فَقَالَتْ إِنَّ أُمِّي تُوُفِّيَتْ وَعَلَيْهَا نَذْرُ صِيَامٍ فَتُوُفِّيَتْ قَبْلَ أَنْ تَقْضِيَهُ . فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لِيَصُمْ عَنْهَا الْوَلِيُّ " .
also referenced under: Hadith 2133 (Reference) & Volume 3, Book 11, Hadith 2133 (DarusSalam)