It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that a woman undertook a sea journey and made a vow that if Allah Almighty saved her from this journey, she would fast for a month. When Allah Almighty granted her safety, she had not yet observed the fasts when she passed away. A female relative of hers came to the Messenger of Allah (peace and blessings be upon him) and related the entire incident. The Prophet (peace and blessings be upon him) said: Fast on her behalf.