It wasnarrated from Ibn 'Umar that the Messenger of Allah (ﷺ)said:
'Whoever dies owing the fasts of a month, one poor person shouldbefed on his behalf for each day." (RU)
English reference (RU): Vol. 1, Book 7, Hadith 1757 (RU)
Arabic reference (RU): Book 7, Hadith 1829 (RU)