حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، عَنْ عُثْمَانَ بْنِ عَطَاءٍ، عَنْ أَبِيهِ، عَنْ أَبِي الدَّرْدَاءِ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ ‏"‏ إِنَّهُ لَيَسْتَغْفِرُ لِلْعَالِمِ مَنْ فِي السَّمَوَاتِ وَمَنْ فِي الأَرْضِ حَتَّى الْحِيتَانِ فِي الْبَحْرِ ‏"‏ ‏.‏

'Abdullah bin Abu Qatadah narrated that his father said

"The Messenger of Allah said: 'The best things that a man can leave behind are three: A righteous son who will pray for him, ongoing charity whose reward will reach him, and knowledge which is acted upon after his death.'" (Hasan)Another chain with similar wording.