It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that a woman made a vow to perform Hajj but she passed away. Her brother came to the Messenger of Allah (peace and blessings be upon him) and asked about this matter. The Messenger of Allah (peace and blessings be upon him) said to him: "If she had a debt, would you pay it off?" He replied: Yes. He said: "Fulfill Allah’s debt, for Allah is more deserving of fulfillment." The narrator said: So the brother fasted on behalf of his sister.