Musnad Ahmad 26:616

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and Yahya narrated to us, from Shu'bah, from Abu Ishaq, from 'Amr ibn Maymun, from 'Abdullah, that he said: We were with the Messenger of Allah, may Allah bless him and grant him peace, in a tent, numbering about forty. He said: "Are you pleased to be a quarter of the people of Paradise?" We said: "Yes." He said: "Are you pleased to be a third of the people of Paradise?" We said: "Yes." He said: "By the One in Whose hand is the soul of Muhammad, I truly hope that you will be half of the people of Paradise. That is because no one shall enter Paradise except a Muslim soul, and you, among the people of polytheism, are only like a white hair on the hide of a black bull, or a black hair on the hide of a red bull."