Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Abdullah bin Amr, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "Learn the Qur'an from four persons: Abdullah bin Mas'ud, Ubayy bin Ka'b, Mu'adh bin Jabal, and the freed slave of Abu Hudhaifah, Salim."