It was narrated from Ibn 'Abbas (رضي الله عنه) that a woman vowed to do Hajj, then she died. Her brother came to the Prophet (ﷺ) and asked him about that, and he said:

“Do you think that if your sister owed a debt, would you pay if off for her?" He said: Yes. He said: “So pay off what is due to Allah, for He is more deserving that what is due to Him should be paid."