Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) says: I heard the Messenger of Allah (peace and blessings be upon him) say: "Learn the Qur'an from four: from Abdullah bin Mas'ud" (and he (peace and blessings be upon him) began with him) "and from Ubayy bin Ka'b, Mu'adh bin Jabal, and Salim the freed slave of Abu Hudhayfah."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8380