Sahih Bukhari Volume 6, Book 61, Hadith Number 521.
Narrated By Masriq : ‘Abdullah bin ‘Amr mentioned ‘Abdullah bin Masud and said, “I shall ever love that man, for I heard the Prophet saying, ‘Take (learn) the Qur’an from four: ‘Abdullah bin Masud, Salim, Mu’adh and Ubai bin Ka’b.'”