Musnad Ahmad 3:14

Muhammad ibn Ja‘far, Bahz, and Hajjaj narrated to us, they said: Shu‘bah narrated to us, he said: I heard ‘Alqamah ibn Marthad narrating from Sa‘d ibn ‘Ubaydah, from Abu ‘Abd al-Rahman al-Sulami, from ‘Uthman ibn ‘Affan, from the Prophet, may God bless him and grant him peace, that he said: "Indeed, the best of you is he who taught the Qur’an or learned it." Muhammad ibn Ja‘far and Hajjaj said: He said: So Abu ‘Abd al-Rahman said: "That is what seated me in this seat." Hajjaj said: Shu‘bah said: Abu ‘Abd al-Rahman did not hear from ‘Uthman nor from ‘Abdullah, but he did hear from ‘Ali, may God be pleased with him. My father said: And Bahz said, from Shu‘bah, he said: ‘Alqamah ibn Marthad informed me, and he said: "The best of you is he who learned the Qur’an and taught it."