Masruq reported: We used to go to Abdullah b. 'Amr and talk to him, Ibn Numair said: One day we made a mention of Abdullah b. Mas'ud, whereupon he said: You have made mention of a person whom I love more than anything else. I heard Allah's Messenger ﷺ as saying: Learn Qur'an from four persons: Ibn Umm 'Abd (i. e. 'Abdullah b. Mas'ud) he started from him-then Mu'adh b. Jabal and Ubayy b. Ka'b, then Salim the ally of Abu Hudhaifa.
It also teaches us that we should respect those who have knowledge even if they are not necessarily our teachers or mentors because they may still be able to provide us with valuable insight into our faith which can help us grow spiritually and become better Muslims overall.