Sunan Ibn Majah, Chapter: The Chapters on Ascetism (Zuhd)

"We were with the Messenger of Allah (saw) in a tent, and he said: Will it not please you to be one quarter of the people of Paradise? We said: Yes. He said: Will it not please you to be one third of the people of Paradise? We said: Yes. He said: By the One in Whose Hand is my soul, I hope that you will be half of the people of Paradise. For no one will enter Paradise but a Muslim soul, and among the people of polytheism you are like a white hair on the hide of a black bull, or like a black hair on the hide of a red bull."