Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that a woman came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah! My sister has passed away and she owed two consecutive months of fasting (should I fast on her behalf?), the Prophet (peace and blessings be upon him) said: Tell me, if your sister had a debt, would you pay it off? She said: Yes! He said: Then Allah’s right is even more deserving to be fulfilled.