From Sahih Bukhari (Hadith 3808):
Narrated Masruq:`Abdullah bin Masud was mentioned before `Abdullah bin `Amr who said, "That is a man I still love, as I heard the Prophet (ﷺ) saying 'Learn the recitation of Qur'an from four from `Abdullah bin Mas`ud -- he started with him--Salim, the freed slave of Abu Hudaifa, Mu`adh bin Jabal and Ubai bin Ka`b
Reference: Bukhari 3808