Muwatta Malik, Book 15, Hadith 510 (In-Book)

Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyab used to say, "A man is raised by the dua of his son after his death." He spoke with his hands turned upwards, and then lifted them up.

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، كَانَ يَقُولُ إِنَّ الرَّجُلَ لَيُرْفَعُ بِدُعَاءِ وَلَدِهِ مِنْ بَعْدِهِ وَقَالَ بِيَدَيْهِ نَحْوَ السَّمَاءِ فَرَفَعَهُمَا ‏.‏

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also referenced under: Book 15, Hadith 38 (USC-MSA)