Musnad Ahmad 26:114

Yahya narrated to us, from Shu'bah, Abu Ishaq narrated to us, from 'Amr ibn Maymun, from 'Abdullah, who said: We were with the Prophet, peace and blessings of Allah be upon him, 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 my soul, I truly hope that you will be half of the people of Paradise. And that is because no one shall enter Paradise except a Muslim soul, and you, in relation to the polytheists, are only like a white hair on the hide of a black bull, or a black hair on the hide of a red bull."