Sunan an-Nasa'i 3816
سنن النسائي#3816SahihIt 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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 35:56