Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that a woman came to the Prophet (peace and blessings be upon him) saying: My mother has died and she owed fifteen days of fasting. He (peace and blessings be upon him) said: "If she had owed a debt, would you have paid it?" She said: Yes. He (peace and blessings be upon him) said: "Pay your mother's debt." She was a woman from Khath'am.
The Shaykh said: Buraydah bin Husayb (may Allah be pleased with him) also narrated it from the Prophet (peace and blessings be upon him) concerning both fasting and Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8230