عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ: ((أَيُّمَا مَيِّتٍ مَاتَ وَعَلَيْهِ صِيَامٌ فَلْيَصُمْهُ عَنْهُ وَلِيُّهُ))
Narrated by Sayyidah Aisha (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: Whoever dies while he still has fasts due upon him, then his relative should fast on his behalf.