رَكِبَتِ امْرَأَةٌ الْبَحْرَ فَنَذَرَتْ أَنْ تَصُومَ شَهْرًا فَمَاتَتْ قَبْلَ أَنْ تَصُومَ فَأَتَتْ أُخْتُهَا النَّبِيَّ صلى الله عليه وسلم وَذَكَرَتْ ذَلِكَ لَهُ فَأَمَرَهَا أَنْ تَصُومَ عَنْهَا .
It was narrated that Ibn 'Abbas said: "A woman traveled by sea and vowed to fast for a month, but she died before she could fast. Her sister came to the Prophet and told him about that, and he told her to fast on her behalf."