Musnad Ahmad 27:198

Yahya ibn Sa'id narrated to us, from 'Ubayd Allah, from Nafi', from Ibn 'Umar, who said: I do not know it except from the Prophet, may Allah bless him and grant him peace, that he said: "Every intoxicant is Khamr (wine/intoxicant), and every intoxicant is unlawful."