Musnad Ahmad 482:124

Abu Abd al-Rahman narrated to us, Ibn Lahi'ah narrated to us, from Abu Qubayl, who said: I did not hear from Uqbah ibn Amir except this hadith. Ibn Lahi'ah said: And Yazid ibn Abi Habib narrated it to me, from Abu al-Khayr, from Uqbah ibn Amir al-Juhani, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "The destruction of my nation is in the Book and the milk." They said: O Messenger of Allah, what are the Book and the milk? He said: "They learn the Quran and interpret it in a way other than what Allah revealed, and they love milk, so they abandon the congregations and the Friday prayers, and they go out to the desert."