Abdullah bin Abbas reported,

A man came to the Prophet ﷺ and said, "Messenger of Allah, my mother has died, and she owed a month of fasting. Shall I make it up on her behalf?"He replied, "If your mother had a debt, would you pay it off for her?"The man said, "Yes."He said, "Then a debt owed to Allah is even more deserving of being paid."Sulayman said, Hakam and Salama bin Kuhayl both said, while we were sitting when Muslim narrated this hadith, "We heard Mujahid mention this from Ibn Abbas."

Azami 4624

Sahih

عن ابن عباس، قال

جاء رجل إلى النبي ﷺ، فقال: يا رسول الله، إن أمي ماتت وعليها صوم شهر، أفأقضيه عنها؟ فقال: لو كان على أمك دين أكنت قاضيه عنها؟ قال: نعم. قال: فدين الله أحق أن يقضى. قال سليمان: فقال الحكم، وسلمة بن كهيل جميعا- ونحن جلوس حين حدث مسلم بهذا الحديث- فقالا: سمعنا مجاهدا يذكر هذا عن ابن عباس.

الأعظمي 4624صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Fasting
Chapter
What is permitted and what is not permitted for the fasting person
Section
Fulfilling fasting on behalf of the deceased
Numbering
Jami al-Kamil 4624 (2nd edition)
Azami 4624