Musnad Ahmad 25:460

'Affan narrated to us, Shu'bah narrated to us, from Qatadah, he said: I heard Abu al-'Aliyah, he said: I heard the cousin of your Prophet, may Allah bless him and grant him peace, Ibn 'Abbas, from the Prophet, may Allah bless him and grant him peace. And Bahz said: Shu'bah narrated to us, Qatadah informed me, from Abu al-'Aliyah, he said: The cousin of your Prophet, may Allah bless him and grant him peace, Ibn 'Abbas narrated to me, he said: The Messenger of Allah, may Allah bless him and grant him peace, said: "It is not fitting for a servant" — 'Affan said: "a servant of mine" — "to say: I am better than Yunus ibn Matta," and he attributed him to his father.