"I heard the Messenger of Allah say: 'Everyone in the universe, in the heavens and on earth, prays for forgiveness for the scholar, even the fish in the sea."  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ إِنَّهُ لَيَسْتَغْفِرُ لِلْعَالِمِ مَنْ فِي السَّمَوَاتِ وَمَنْ فِي الأَرْضِ حَتَّى الْحِيتَانِ فِي الْبَحْرِ  

The Prophet said: "Whoever teaches some knowledge will have the reward of the one who acts upon it, without that detracting from his reward in the slightest."  

أَنَّ النَّبِيَّ ﷺ قَالَ مَنْ عَلَّمَ عِلْمًا فَلَهُ أَجْرُ مَنْ عَمِلَ بِهِ لاَ يَنْقُصُ مِنْ أَجْرِ الْعَامِلِ  

"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.  

قَالَ رَسُولُ اللَّهِ ﷺ خَيْرُ مَا يُخَلِّفُ الرَّجُلُ مِنْ بَعْدِهِ ثَلاَثٌ وَلَدٌ صَالِحٌ يَدْعُو لَهُ وَصَدَقَةٌ تَجْرِي يَبْلُغُهُ أَجْرُهَا وَعِلْمٌ يُعْمَلُ بِهِ مِنْ بَعْدِهِ قَالَ أَبُو الْحَسَنِ وَحَدَّثَنَا أَبُو حَاتِمٍ حَدَّثَنَا مُحَمَّدُ بْنُ يَزِيدَ بْنِ سِنَانٍ الرَّهَاوِيُّ حَدَّثَنَا يَزِيدُ بْنُ سِنَانٍ يَعْنِي أَبَاهُ حَدَّثَنِي زَيْدُ بْنُ أَبِي أُنَيْسَةَ عَنْ فُلَيْحِ بْنِ سُلَيْمَانَ عَنْ زَيْدِ بْنِ أَسْلَمَ عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ عَنْ أَبِيهِ سَمِعْتُ رَسُولَ اللَّهِ ﷺ فَذَكَرَ نَحْوَهُ  

"The Messenger of Allah said: 'The rewards of the good deeds that will reach a believer after his death are: Knowledge which he taught and spread; a righteous son whom he leaves behind; a copy of the Qur'an that he leaves as a legacy; a mosque that he built; a house that he built for wayfarers; a canal that he dug; or charity that he gave during his lifetime when he was in good health. These deeds will reach him after his death.'"  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّ مِمَّا يَلْحَقُ الْمُؤْمِنَ مِنْ عَمَلِهِ وَحَسَنَاتِهِ بَعْدَ مَوْتِهِ عِلْمًا عَلَّمَهُ وَنَشَرَهُ وَوَلَدًا صَالِحًا تَرَكَهُ وَمُصْحَفًا وَرَّثَهُ أَوْ مَسْجِدًا بَنَاهُ أَوْ بَيْتًا لاِبْنِ السَّبِيلِ بَنَاهُ أَوْ نَهْرًا أَجْرَاهُ أَوْ صَدَقَةً أَخْرَجَهَا مِنْ مَالِهِ فِي صِحَّتِهِ وَحَيَاتِهِ يَلْحَقُهُ مِنْ بَعْدِ مَوْتِهِ  

The Prophet said: "The best of charity is when a Muslim man gains knowledge, then he teaches it to his Muslim brother."  

أَنَّ النَّبِيَّ ﷺ قَالَ أَفْضَلُ الصَّدَقَةِ أَنْ يَتَعَلَّمَ الْمَرْءُ الْمُسْلِمُ عِلْمًا ثُمَّ يُعَلِّمَهُ أَخَاهُ الْمُسْلِمَ