The reward of the one teaching the people the good Sunan Ibn Majah 240

Arabic hadith text
حَدَّثَنَا أَحْمَدُ بْنُ عِيسَى الْمِصْرِيُّ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، عَنْ يَحْيَى بْنِ أَيُّوبَ، عَنْ سَهْلِ بْنِ مُعَاذِ بْنِ أَنَسٍ، عَنْ أَبِيهِ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ قَالَ ‏"‏ مَنْ عَلَّمَ عِلْمًا فَلَهُ أَجْرُ مَنْ عَمِلَ بِهِ لاَ يَنْقُصُ مِنْ أَجْرِ الْعَامِلِ ‏"
Translation
Sahl bin Mu'adh bin Anas narrated from his father that

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."