Musnad Ahmad 28:310

Abu Mu'awiyah narrated to us, Al-A'mash narrated to us, from Shaqiq, from Masruq, from Abdullah ibn 'Amr, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "Take the Quran from four: from Ibn Mas'ud, Ubayy ibn Ka'b, Mu'adh ibn Jabal, and Salim, the freed slave of Abu Hudhayfah." He said: Abdullah said: "That is a man whom I will never cease to love, ever since I saw the Messenger of Allah, peace and blessings of Allah be upon him, begin with him."