Sunan an-Nasa'i 3816

Bishr ibn Khalid al-ʿAskari reported to us; he said: Muhammad ibn Jaʿfar narrated to us, from Shuʿbah, who said: I heard Sulayman narrate from Muslim al-Batin, from Saʿid ibn Jubayr, from Ibn ʿAbbas, who said: A woman traveled by sea and vowed to fast for a month, but she died before fasting. Her sister came to the Prophet, peace and blessings be upon him, and told him about it. He instructed her to fast on her sister’s behalf.