Harmalah ibn Yahya narrated to me, Ibn Wahb informed us, Yunus informed me, that Ibn Shihab informed him, from Hamzah ibn 'Abdullah ibn 'Umar ibn al-Khattab, from his father, from the Messenger of Allah, peace and blessings be upon him, who said: "While I was sleeping, I saw a cup brought to me containing milk, and I drank from it until I could see the wetness flowing through my nails. Then I gave my remaining milk to 'Umar ibn al-Khattab." They said, "How did you interpret that, O Messenger of Allah?" He said, "Knowledge."