Masruq says: We mentioned Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) in the presence of Sayyiduna Abdullah bin Amr (may Allah be pleased with them both), and Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) said: That is a man whom I will always love, after something I heard from the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) said: "Learn the Qur'an from four people: from Ibn Umm Abd" (and he (peace and blessings be upon him) began with him) "and from Ubayy bin Ka'b, and from Salim the freed slave of Abu Hudhayfah, and from Mu'adh bin Jabal."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8378