أَخْبَرَنَا أَحْمَدُ بْنُ حَفْصِ بْنِ عَبْدِ اللَّهِ النَّيْسَابُورِيُّ، قَالَ حَدَّثَنِي أَبِي قَالَ، حَدَّثَنِي إِبْرَاهِيمُ بْنُ طَهْمَانَ، عَنْ عُمَرَ بْنِ سَعِيدٍ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّ أَطْيَبَ مَا أَكَلَ الرَّجُلُ مِنْ كَسْبِهِ وَإِنَّ وَلَدَهُ مِنْ كَسْبِهِ ‏"‏ ‏.‏

It was narrated that 'Aishah said: "The Messenger of Allah said: 'The best (most pure) food that a man eats is that which he has earned himself, and his child (and his child's wealth) is part of his earning." Translation Not Available

Book Ref: Sunan An Nisai Book 44 Hadith 4452
Web Ref:  Sunan An Nisai Vol 5 Book 44 Hadith 4457