It was narrated from Ibn 'Abbas (رضي الله عنه) from

The Prophet (ﷺ). He said: A woman came to him and said: My mother has died and she owed the fast of the month of Ramadan; should I make it up on her behalf? He said: “Do you think that if she owed a debt, you would pay it off?” She said: Yes. He said: “The debt of Allah, may He be glorified and exalted, is more deserving of being paid off.”