Musnad Ahmad 1017:98

Zayd ibn al-Hubab narrated to us, Malik ibn Mighwal informed me, Abdullah ibn Buraydah narrated to us, from his father, that the Messenger of Allah (peace and blessings of Allah be upon him) entered the mosque, and he took my hand, so I entered with him. Suddenly, there was a man reciting and praying. He said: "This man has been given a flute from the flutes of the family of David." And it was Abdullah ibn Qays, Abu Musa al-Ash'ari. He said: I said, "O Messenger of Allah, shall I inform him?" He said: So I informed him. He said: "You have always been a friend to me."