أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنَا الْعَلاَءُ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِذَا مَاتَ الإِنْسَانُ انْقَطَعَ عَمَلُهُ إِلاَّ مِنْ ثَلاَثَةٍ مِنْ صَدَقَةٍ جَارِيَةٍ وَعِلْمٍ يُنْتَفَعُ بِهِ وَوَلَدٍ صَالِحٍ يَدْعُو لَهُ ‏"‏‏.‏

It was narrated from Sa'd bin 'Ubadah that he came to the Prophet and said

"My mother has died and she had a vow to fulfill. Will it suffice if I free a slave on her behalf?" He said: "Free a slave on behalf of your mother."