Narrated Abu 'Abdur-Rahman:
from 'Uthman bin 'Affan that the Messenger of Allah (ﷺ) said: "The best of you is he who learns the Qur'an and teaches it." Abu 'Abdur-Rahman said: "So that is why I sit at this seat of mine." And he taught the Qur'an during the time of 'Uthman until Al-Hajjaj bin Yusuf came. (ES)
English reference (ES): Vol. 5, Book 42, Hadith 2907 (ES)
Arabic reference (ES): Book 45, Hadith 3154 (ES)